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

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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 •608 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

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SLIDE 1

WiB

A New System Concept for DTT

Erik Stare, Teracom

  • Dr. Jordi J. Giménez, UPV
  • Dr. Peter Klenner, Panasonic Europe Ltd
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SLIDE 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…
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SLIDE 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?
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SLIDE 4

Traditional frequency planning

  • 400
  • 300
  • 200
  • 100

100 200 300 400

  • 300
  • 200
  • 100

100 200 300

1

2 3 4 5 6 7

1

2 3 4 5 6 7

1

2 3 4 5 6 7

1

2 3 4 5 6 7

1

2 3 4 5 6 7

1

2 3 4 5 6 7

1

2 3 4 5 6 7 km km

reuse-7 NOTE: Reuse is required also with SFN at content borders! (e.g. reuse-4) Only a fraction of the UHF channels are used from a given site

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SLIDE 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
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SLIDE 6

Frequency Power [W]

(drawn to scale)

UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF24 UHF25 UHF26 UHF27 UHF28

DVB-T2 Mux 1

…

2500 DVB-T2 Mux 2 DVB-T2 Mux 6 No power

…

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

Earlier studies: Higher capacity and lower power consumption with a lower reuse factor!

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SLIDE 7

What about reuse-1?

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SLIDE 8

Frequency Power [W]

(drawn to scale)

UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF9 UHF10

WiB …

UHF24 UHF25 UHF26 UHF27 UHF28

DVB-T2 Mux 6 DVB-T2 Mux 2 DVB-T2 Mux 1

…

2500 50

17 dB difference per RF channel Factor 50!

WiB - Spreading the power equally over all frequencies

(reuse-1)

About 90% less total TX power by using all frequencies

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SLIDE 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”

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SLIDE 10
  • High basic robustness (close to C/I=0 dB)
  • Rejection via RX antenna

‒ Rooftop: Directional antenna

 Antenna discrimination 16 dB (ITU)

‒ Mobile: Dynamic beamforming

  • Interference cancellation

TX1 TX2 TX3 RX SFN 1 SFN 2 SFN 3 RX

How to handle interference

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SLIDE 11

TX1 TX2 TX3 RX

N=1 C3=1 C2=2 C1=4 N=1 C3=1 C2=2

Demodulated and cancelled

N=1 C3=1

Demodulated and cancelled

Demodulated

Required C/N = 0 dB (linear 1)

TX1 TX2 RX

Cancellation

  • f TX2

Interference cancellation

All TXs are synchronised (similar to SFN) but with different content and pilots

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SLIDE 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
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SLIDE 13

Network performance simulations

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

  • 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

DVB-T2 today: about 1 bps/Hz

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SLIDE 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

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SLIDE 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

Time Capacity [Mbps]

TV service #4 TV service #3 TV service #2 TV service #1 PSI/SI, CA, bootloading etc

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SLIDE 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

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SLIDE 17

Introduction scenarios

  • Dedicated band approach
  • Interleaved approach
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SLIDE 18

Introduction scenarios -

Dedicated band approach

DTT 470-862 MHz DTT 470-790 MHz DTT 470-694 MHz DTT

800 MHz band 700 MHz band

WiB

800 MHz band 800 MHz band

WiB 470-694 MHz

700 MHz band 800 MHz band 700 MHz band

  • 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

time

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SLIDE 19

Introduction scenarios -

Interleaved approach

UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF9 UHF10

…

UHF24 UHF25 UHF26 UHF27 UHF28 UHF1 UHF2 UHF3 UHF4 UHF5 UHF6 UHF7 UHF8 UHF9 UHF10

…

UHF24 UHF25 UHF26 UHF27 UHF28 Wanted TX2 Interfering TX1

T2 T2 T2 T2 T2 T2

Power

  • WiB is introduced ”interleaved” with existing DVB services
  • WiB is transmitted with low power and, if necessary, with opposite

polarisation to minimise disturbance

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SLIDE 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

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SLIDE 21

Instead of this prolonged tug of war…

DTT spectrum Mobile Telecom spectrum

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SLIDE 22

… why not this Win-Win peace project?

DTT Mobile Telecom

Same spectrum (100% of time, 100% of frequency)

Mobile Telecom receivers first demodulate and cancel DTT Mobile Telecom signals are ”invisible” for DTT receivers Controlled level distance Separated via Interference Cancellation

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SLIDE 23

A WiB Vision

Same system/standard for broadcast and unicast

5G New Radio - Broadcast 5G New Radio - Unicast

Same system/standard

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SLIDE 24

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

Big enough leap?

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SLIDE 25

Thank you for your attention!

For more information about WiB:

www.teracom.se/wib WiB@IBC: 8.A50 (Progira Radio Communication booth)