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NETWORK CONFIGURATIONS _______ BR Seminar 18-19 September 2003. Jean-Jacques GUITOT ANFR - DPSAI – Dépt Planification – Etudes prospectives Guitot@anfr.fr. Which Reception Mode?. Fixed?. HDTV ou portable?. Mobile?. Portable outdoor or indoor?. Hand portable?.
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NETWORK CONFIGURATIONS_______BR Seminar 18-19 September 2003 Jean-Jacques GUITOT ANFR - DPSAI – Dépt Planification – Etudes prospectives Guitot@anfr.fr
Which Reception Mode? Fixed? HDTV ou portable? Mobile? Portable outdoor or indoor? Hand portable?
Minimum required field strength Illustration of scheme of different receiving conditions for DVB-T DVB-T Transmitter Rice channel Rayleigh channel Rayleigh channel ---------- 10m ---------- 10m Location correction factor = 9dB Height loss dB Height loss dB ---------- 10m Location Correction factor = 9.1 or 13 dB Penetration loss dB Location Correction factor = 4dB ---------- 1,5m ---------- 1,5m (C/N)m (C/N)f (C/N)p Portable reception Mobile reception Fixed reception
Minimum required field strength Minimum median equivalent field strength for a location probability of 95% of locations • +4dB for 99% of locations • + 11 to 15 dB for indoor coverage
Which coverage? • Size of service area • Shape of service area • Percentage of Location probability
Which DTTB Systems? • OFDM, VSB • If OFDM : 2 k, 8K • System variants • Hierarchical , non-hierarchical modulation • QPSK, 16 QAM, 64 QAM • Code rate • bitrate
Which Network Configuration? • MFN : Multi Frequency Network • different frequencies assigned to each site • Coverage provided by a transmitter • SFN : Single Frequency Network • The same frequency assigned to each site • Synchronised • Same content • Self interference to be taken into account for portable and mobile (size limited) • Every transmitter contribute to provide the coverage and cannot operate independently
Which choice of network? • Network Configuration • MFN, SFN • With technical parameters to be taken into account • Antenna height • Antenna directivity • E.r.p. • Distance between sites for MFN or SFN • Re-use of existing sites; • Re-use of existing sites and creation of sites • Complete creation of sites For providing a service coverage
Process for a choice of network imply DTTB Service Reception mode Reception Coverage (% location probability) System; 2K or 8 K, Variant Hierarchical; non-hierarchical Optimisation of network choice Network configuration
Network Configurations in Planning • Configuration modes • MFN • SFN With technical parameters • Antenna heights • Antenna patterns • E.R.P. • Distance between sites and /or • Width and shape of service area
Configurations modes in Planning • MFN : • SFN : implementation by • Few high power stations • More stations but lower radiated power • Main stations complemented by gap-filler (low power stations) • Mixed MFN and SFN • In a same country some coverage are provided by MFN and by SFN • In adjacent countries, one is implementing MFN type, the other SFN type
SFN · synchronous signal · same RF channel · same content
SFN parameters • Guard interval • has a major implication on the topology of SFN implementation • Duration governs the maximum echoes delay admissible by the system : maximum possible distance between co-channel transmitters • More or less Large SFN
OFDM signal parameters That for non-directive antenna
Frequency Planning • Take into account requirements to describe configuration networks • Use technical bases for calculation • Transmitter distances between co-channel for MFN • Separation distances between SFN