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WiB A New System Concept for DTT Erik Stare, Teracom Dr. Jordi J. - PowerPoint PPT Presentation

Jul 18, 2023 •343 likes •603 views

WiB A New System Concept for DTT Erik Stare, Teracom Dr. Jordi J. Gimnez, UPV Dr. Peter Klenner, Panasonic Europe Ltd Background 1 1992: First IBC in Amsterdam Scandinavian HD-DIVINE project Performed the worlds first HW

  1. WiB A New System Concept for DTT Erik Stare, Teracom Dr. Jordi J. Giménez, UPV Dr. Peter Klenner, Panasonic Europe Ltd

  2. Background 1 • 1992: First IBC in Amsterdam – Scandinavian HD-DIVINE project – Performed the world’s first HW demo of HDTV over DTT (OFDM) – Slogan: ” One Big Step for Television” – Enormously successful (” Digital terrestrial breakthrough steals show ”) • Triggered the creation of DVB in 1993 • The rest is history …

  3. Background 2 • Situation today: • Painful process to migrate to new broadcast standards • Difficult to justify a new “DVB - T3” standard without radically improved performance & functionality • Uncertain spectrum situation • A small step is not enough… • Is a “giant leap” possible?

  4. Traditional frequency planning Only a fraction of the UHF channels are used from a given site 4 300 4 3 5 1 3 5 NOTE: 200 1 2 6 Reuse is required 2 6 7 4 100 4 7 3 5 reuse-7 also with SFN 1 3 5 4 1 km at content borders! 0 3 5 2 6 1 2 6 7 (e.g. reuse-4) 7 2 6 4 -100 7 4 3 5 1 3 5 -200 1 2 6 2 6 7 -300 7 -400 -300 -200 -100 0 100 200 300 400 km

  5. Shannon’s law and required power • Capacity is proportional to SNR (power) in dB • Required power increases exponentially with capacity • High capacity also means high sensitivity to interference

  6. Required TX power for traditional DTT Extremely unbalanced RF power across UHF channels – very bad from efficiency point of view! Power [W] (drawn to scale) • Bad for capacity 2500 • Bad for power DVB-T2 DVB-T2 DVB-T2 Mux 1 Mux 2 Mux 6 Earlier studies: Higher capacity and … lower power consumption with a lower reuse factor ! No power Frequency … UHF2 UHF6 UHF7 UHF8 UHF24 UHF25 UHF26 UHF27 UHF28 UHF1 UHF3 UHF4 UHF5

  7. What about reuse-1?

  8. WiB - Spreading the power equally over all frequencies (reuse-1) Power [W] (drawn to scale) 2500 DVB-T2 DVB-T2 … DVB-T2 Mux 1 Mux 2 Mux 6 17 dB difference per RF channel  Factor 50! WiB Frequency … 50 UHF2 UHF6 UHF7 UHF8 UHF9 UHF10 UHF24 UHF25 UHF26 UHF27 UHF28 UHF1 UHF3 UHF4 UHF5 About 90% less total TX power by using all frequencies

  9. Basic principles of WiB • Wideband – Wideband transmission as a single WiB signal • Covering potentially the whole 224 MHz UHF band (28 UHF channels) – Reception with a ”Narrow - wide” (32 MHz) tuner • Allows for high service bit rates also with robust transmission mode – Tuner frequency-hopping around the whole UHF band • Wideband frequency diversity • Reuse-1 – Adjacent TXs use the same frequencies – Very challenging interference situation (e.g. C/I = 0 dB) • Robust transmission mode required – e.g. QPSK, req. C/N close to 0 dB • Interference Cancellation – Removes unwanted interference  WiB = ”WideBand reuse - 1”

  10. How to handle interference TX2 RX • High basic robustness (close to C/I=0 dB) TX1 TX3 • Rejection via RX antenna ‒ Rooftop: Directional antenna  Antenna discrimination 16 dB (ITU) ‒ Mobile: Dynamic beamforming • Interference cancellation SFN 2 RX SFN 1 SFN 3

  11. TX1 Interference cancellation RX Cancellation of TX2 TX2 TX2 All TXs are synchronised RX (similar to SFN) but with Required C/N = 0 dB (linear 1) TX1 different content and pilots TX3 Demodulated C1=4 and cancelled Demodulated and C2=2 C2=2 cancelled C3=1 C3=1 C3=1 Demodulated N=1 N=1 N=1

  12. Receiver complexity • A receiver is not expected to demodulate the 200- 300 Mbps “ supermux ” as a whole – A receiver rather extracts a selected service and demodulates only the associated part of the signal • What we do have: – Factor 4 increase in sampling frequency and FFT size due to wider tuner bandwidth – Additional complexity for frequency-hopping tuner (e.g. TFS) is low – Additional complexity for Interference Cancellation • but rather limited thanks to all TXs being synchronized

  13. Network performance simulations • Effective TX antenna height 250 m • 60 km TX separation • 1 kW ERP per UHF channel (17 dB lower than today) • Propagation according to ITU-R P.1546 • Standard deviation: 5.5 dB (shadow fading) + 2.0 dB (frequency-dependent fading) • Spatial correlation model • Three different time correlation models (C, U1, U2) • Directional RX antenna at 10 m (11 dBd gain, max 16 dB discrimination) • Best TX case: The best TX is chosen irrespective of content • Wanted TX case: A particular TX (with desired content) is required • Interference cancellation of up to 2 TX signals • Spectral efficiency calculated as average (normalized) Shannon capacity (95% probability, 99% of time) in the worst point Time correlation type Best TX Wanted TX Inter/Intra site (C) 3.41 bps/Hz 1.55 bps/Hz DVB-T2 today: about 1 bps/Hz Intra-site (U1) 3.38 bps/Hz 1.37 bps/Hz No correlation (U2) 4.07 bps/Hz 1.60 bps/Hz

  14. System performance simulations • Network performance simulations have treated interference as noise • At 1 bps/Hz no tolerance for noise at C/I=0 dB (Req . C/N=∞) • However, possible to take into account the constellation of the interferer in the demodulation • Allows QPSK demodulation (1 bps/Hz) at C/N=6 dB (instead of infinity) with 0 dB QPSK interferer  Potential for significant performance increase of network simulations

  15. Statistical Multiplexing • With WiB statmuxing may be performed over a statmux pool consisting of (up to) the capacity of the entire WiB signal (e.g. 200-300 Mbps within 470-694 MHz) • Allows for close-to-ideal stamuxing also of UHD services Capacity [Mbps] PSI/SI, CA, bootloading etc TV service #4 TV service #3 TV service #2 TV service #1 Time

  16. Reduced costs • Capital Expenditures (CAPEX) – Single wideband TX • Required total output power about half of one existing DTT TX – No need for combiners - only a single wideband RF filter Combiner room today – Lower equipment volume/weight • May allow mast positioning of the TX  no RF feeder needed – Lower performance requirements on TXs (linearity etc), due to robust transmission – Drastically reduced need for cooling and backup power • Operational Expenditures (OPEX) – >90% lower fundamental energy consumption – Reduced maintenance need (less equipment, less sensitive, longer lifetime) – No need for frequency planning and frequency changes

  17. Introduction scenarios • Dedicated band approach • Interleaved approach

  18. Introduction scenarios - Dedicated band approach DTT 470-862 MHz DTT 470-790 MHz 800 MHz band DTT 470-694 MHz 700 MHz band 800 MHz band DTT WiB 700 MHz band 800 MHz band WiB 470-694 MHz 700 MHz band 800 MHz band time • International agreement on sub-band for WiB introduction • Co-ordinated transition • In the long term the whole 470-694 MHz band may be used for WiB

  19. Introduction scenarios - Interleaved approach • WiB is introduced ”interleaved” with existing DVB services • WiB is transmitted with low power and, if necessary, with opposite polarisation to minimise disturbance Power T2 T2 T2 Interfering … TX1 UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF9 UHF10 UHF24 UHF25 UHF26 UHF27 UHF28 T2 T2 T2 … Wanted TX2 UHF2 UHF6 UHF7 UHF8 UHF9 UHF10 UHF24 UHF25 UHF26 UHF27 UHF28 UHF1 UHF3 UHF4 UHF5

  20. Extension of the basic WiB concept (examples) • Cross-polar MIMO (H + V polarisation on the same frequency) – May further double the WiB capacity – Could be backwards-compatible with legacy RX antennas • Sufficient separation via RX antenna polarization discrimination (16 dB) • LDM-based combination of broadcast and unicast (mobile telecom) in the same spectrum – Transmission on the same time/frequency (e.g. on the same ” resource block ”) with controlled power difference – Separated in the receiver by interference cancellation

  21. Instead of this prolonged tug of war … DTT spectrum Mobile Telecom spectrum

  22. … why not this Win-Win peace project? Controlled level Mobile Telecom signals are DTT distance ” invisible ” for DTT receivers Mobile Telecom receivers first Separated via Mobile Telecom demodulate and cancel DTT Interference Cancellation Same spectrum (100% of time, 100% of frequency)

  23. A WiB Vision Same system/standard for broadcast and unicast 5G New Radio - Broadcast 5G New Radio - Unicast Same system/standard

  24. Big enough leap? WiB gain summary • Increased spectral efficiency • Radically reduced network cost • Unconstrained use of local services • Close-to-ideal statmux gain (video coding) – also for U-HDTV • High speed mobile reception of all “roof - top” services • Commercially acceptable introduction/migration scenarios • Converged win-win solution with mobile telecom

  25. For more information about WiB: www.teracom.se/wib WiB@IBC: 8.A50 (Progira Radio Communication booth) Thank you for your attention!

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