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

Transcription

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

2 Background : 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 reuse-7 km NOTE: Reuse is required also with SFN at content borders! (e.g. reuse-4) 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 Power [W] (drawn to scale) 2500 Required TX power for traditional DTT Extremely unbalanced RF power across UHF channels very bad from efficiency point of view! Bad for capacity Bad for power DVB-T2 Mux 1 DVB-T2 Mux 2 DVB-T2 Mux 6 Earlier studies: Higher capacity and lower power consumption with a lower reuse factor! No power Frequency UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF24 UHF25 UHF26 UHF27 UHF28

7 What about reuse-1?

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

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 High basic robustness (close to C/I=0 db) Rejection via RX antenna Rooftop: Directional antenna Antenna discrimination 16 db (ITU) Mobile: Dynamic beamforming TX1 RX TX3 Interference cancellation SFN 2 SFN 1 RX SFN 3

11 Interference cancellation TX1 RX Cancellation of TX2 TX2 TX2 Required C/N = 0 db (linear 1) TX1 RX TX3 All TXs are synchronised (similar to SFN) but with different content and pilots C1=4 Demodulated and cancelled C2=2 C2=2 Demodulated and 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 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) 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 Intra-site (U1) 3.38 bps/hz 1.37 bps/hz No correlation (U2) 4.07 bps/hz 1.60 bps/hz DVB-T2 today: about 1 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 Mbps within 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 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 Combiner room today

17 Introduction scenarios Dedicated band approach Interleaved approach

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

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

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 distance Separated via Interference Cancellation DTT Mobile Telecom Mobile Telecom signals are invisible for DTT receivers Mobile Telecom receivers first demodulate and cancel DTT 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 WiB gain summary Big enough leap? 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: 8.A50 (Progira Radio Communication booth) Thank you for your attention!