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Implementation Issues: SI & CA

Implementation Issues: SI & CA. Martin Gold NDS. Overview of SI Discussion. SI Implementation issues for Tuning to Transport Streams Selection of Services Event Information Use of IDs Common issues are Choosing from optional DVB data

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Implementation Issues: SI & CA

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  1. Implementation Issues: SI & CA Martin Gold NDS

  2. Overview of SI Discussion • SI Implementation issues for • Tuning to Transport Streams • Selection of Services • Event Information • Use of IDs • Common issues are • Choosing from optional DVB data • System guidelines - more complex approaches require more rules for transmission and receiver • “Private” extensions and local interpretations

  3. SI: Tuning to Transport Streams • Scan tune • Ensures coverage of all services at time of scan • Simple algorithm • SI used to identify signals • Additional frequency list not required • User intervention needed for new transmissions • May be slow if many modulation parameter variables

  4. SI: Tuning to Transport Streams • SI directed search • Need to start somewhere - pre-determined, keyed in, or scanned • NIT data needs to describe “other” transmissions in consistent manner • Alternative frequencies for Terrestrial transmission makes algorithm complicated • Issues: • Scope of particular Network (Network_id) • Rules for completeness of NIT transmission • Rules for transmission parameter options

  5. SI: Service Selection • Receiver needs to form a list of services to offer user • Require consistent results otherwise user is confused • Issues: • Rules for transmission of SDT other • Use of BAT • Use of Mosaic Services • “Logical” Channel Numbers

  6. SI: Event Information • Event data dominates SI bit-rate • One or more Services per Transport Stream • Many events per Service • Memory-bandwidth trade-off: • Trade-off: Not enough memory, not enough bandwidth! • Potential for optimisation of transmission with knowledge of storage capability of receiver • Data repetition rate determined by access-time or memory loading time. • Data could be mainly on one transport stream

  7. SI: Event Information • EIT other (“cross-carriage”) • Becomes more desirable with lower repetition rates • Requires co-operation and sharing of data between broadcasters • Central collation of schedules and central SI generation easier than “mixing”data in SI format. • Complexity may not justify the benefits.

  8. SI: Event Information • Example Data Size • 10 services • 8 days schedule • 45 minute average event length • 100 bytes average text name & description • Data ~350kbytes • Bit-rate: 280kbit/s for 10 second repetition rate

  9. SI: Local Adaptation • Choice of language(s) • Interpretation of parental rating • match to FACTS/ABA TV PG Classifications • Interpretation of country_region_id for time zones

  10. SI: Use of IDs • Values to be assigned by ETSI: • Network_ids • Original_Network_ids • Bouquet_ids • Unique combinations: • Original_network_id & transport_stream_id • Original_network_id & service_id • Original_network_id & service_id & event_id (during period of EIT schedule depth)

  11. Example - “Grid” from EIT Schedule

  12. Example: Event Details

  13. Example: Selection by Genre

  14. Example: Selection by Genre

  15. Overview of CA Discussion • CA capabilities • Scope of DVB Standards • Multicrypt & Simulcrypt

  16. CA Capabilities • Charging for Services (subscriptions and PPV) • Addressing particular users/receivers • By any characteristic of user/receiver known by SMS • Authentication • Transmitted data • User identity

  17. CA Capabilities • Supports Software Download • Addressing particular receivers • Particular make/model • Trial downloads • Secure authentication to avoid receiver “hacking” • Can encrypt software and charge users for it

  18. DVB Standardisation of CA • DVB scrambling • Data transport of ECMs and EMMs • Multicrypt model • Common Interface specification for receiver CA module • Simulcrypt model • Specification for interfaces between CA and compression systems

  19. Simulcrypt • Allows service to be accessible to receivers with different CA Systems • Most existing DVB CA systems implemented prior to Simulcrypt specification • Part 1 now coming into operational use • Part 2 close to ETSI standard. Introduces standard interfaces for “custom” PSI and SI insertion from CA system to compression system • Part 2 implementations not yet available from CA and compression system vendors • CA functions of different CA systems not identical

  20. Multicrypt • Allows Receiver to support multiple CA systems via plug-in module • Module has PCMCIA format • Usually smart card also • Higher cost than embedded CA system • Expensive for consumer, particularly if multiple modules needed • Limited support for PPV through Common Interface

  21. Conclusions • SI • Choices of which optional data will be transmitted • Use of national interpretations and extensions • System Rules of Operation needed • specify transmission against assumed receiver model(s) • CA • Introduction of CA services likely to drive implementation • Useful also for addressing capability and for software download

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