Regional Information Meeting and Workshop relatedto the RRC06 for the administrations of the African

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Regional Information Meeting and Workshop
related to the RRC-06 for the administrations of
the African countriesDakar, Senegal, 25-29 April
2005

• Planning for DVB-T and T-DAB services
• Some practical considerations

Pham Nhu Hai Radiocommunication Bureau
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Outline

• Digital world!
• Policy objectives
• Planning objectives
• Planning methodology

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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

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Digital world!!

• Brick wall reception effect (4 to 1 2dB)

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Digital world!!!

• Reception modes
• Fixed
• Portable indoor
• Portable outdoor
• Mobile

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Digital world!!!

• Single Frequency networks (SFN)

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Policy 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?

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Policy 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?

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Planning objectives?

• Simulcast of analogue and digital
• Digital analogue coverage as soon as possible
• Portable reception modes in urban centers and
  fixed for outskirt areas
• Quality of service High definition?
• Number of services

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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

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Which reception mode?

• DVB-T
• Fixed
• Portable outdoor and indoor
• Mobile
• Main population portable
• Outlying areas - Fixed
• T-DAB
• Mobile
• Portable indoor

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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

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Network structure?

• Multi Frequency Network (MFN)
• Single Frequency Network (SFN)

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Multi frequency network MFN

• Each transmitter operates on a different
  frequency
• Overlaps between transmitters possible
• Regional or local programming
• Ideal for conversion of existing analogue services

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Single 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

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Planning criteria

• Minimise interference and disruption to analogue
  services
• Minimise cost to viewers and broadcasters
• Use of existing transmitting facilities
• Consideration of existing receive antennas
• Identify a minimum of N channels

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One planning approach

• Determine minimum median field strength
• System variants
• Reception mode
• Determine ERP required to provide desired
  coverage
• Propagation models
• Tx site
• Receive antenna

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One planning approach..

• Calculate available protection ratio
• APRW-UADPD
• Where
• 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

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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

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Conclusions

• Clear planning objectives
• National planning ltgt RRC planning
• Consideration of existing transmitting and
  receive facilities
• Use experience from the operation of analogue
  services
• Carry out tests if necessary

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Thanks for your attention