The Office of Communications, commonly known as Ofcom, is the government-approved regulatory and competition authority for the broadcasting, telecommunications and postal industries of the United Kingdom. Ofcom held a technical demonstration of small-scale DAB broadcasting at Ofcom's facility at Baldock, Hertfordshire, on 13 November 2014 ahead of a technical trial of the platform starting in 2015.

1. Small scale DAB technical event
13 November 2014

2. Agenda
• Presentation 09.30 – 10.00 13.00 – 13.30
– Technical development so far
– Trial licensing
• Demonstrations 10.00 – 12.00 13.30 – 15.30
– Single transmitter
– Satellite gap filler
– On-channel repeater
• Q&A session 12.00 – 12.30 15.30 – 16.00
• Lunch 12.30 – 13.00 12.30 – 13.00
• Tour of Baldock facilities (optional)
• Coach departs for Baldock station 13.00 16.30
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Morning session Afternoon session

3. Introduction
Peter Madry
Principal, Spectrum Policy Group
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4. Small-scale DAB: the story so far
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• The existing DAB platform is not well-suited for carrying smaller radio
services, primarily because of the cost and the coverage.
• The Brighton trial suggested there may be another way of doing things which
could work well for small stations.
• The Government is so interested in this it is giving us money to explore
further.
• This event is an opportunity for us to explain the progress made since
Brighton and to demonstrate some of the technical infrastructure in use.

5. What is the objective?
• The work we intend to do over the next two years has two main objectives:
– To further test the practicality of implementing the approach used in the
Brighton trial.
– To design an appropriate licensing framework which would enable small-
scale DAB services to broadcast.
• We believe that any ‘solutions’ should be:
– simple
– cost-effective
– flexible
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6. Technical development so far
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7. Analogue vs Digital – what’s the difference?
• Analogue
– Provides one service per channel, and set of infrastructure
– Graceful fade
– Universal quality
– Simple transmission chain
• Digital
– Typically provides multiple services (with mostly uniform coverage)
– Digital cliff
– Quality tailoring between services
– More complex transmission chain
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8. Traditional DAB transmission chain
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Audio ISO Encoders
(One for each service)
Ensemble Multiplexer
COFDM Modulator
RF Linear Amplifier
Spectrum Mask Filter
Not economical for small areas!
E1 Leased Lines

9. Low cost approach
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Audio ISO Encoders,
Multiplexer and
Modulator on single PC
Software Defined Radio
RF Linear Amplifier
Simpler filtering?

10. Typical transmitter architecture
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Mask filterPower
amplifier
Software
defined radio
Multiplexer &
modulator
Sound programme service 1
provider Transmitting
antenna
Feeder
cableDistribution
(internet)
Transmitter site
Encoder
Encoder
Sound programme service 2
provider
Audio
Audio

11. Developments since Brighton trial
Encoder Multiplexer Modulator
TooLAME-DAB ODR-DabMux ODR-DabMod
MPEG 1 Layer 2 audio encoder DAB multiplexer EN 300 401 compliant modulator
Achieved:
• Professional sound server
input
• ARM support
• Improved configuration file
support
• Time stamping for SFN
operation
• MP2 input and ETI output
than can operate with
encoder and modulator
• Remote control for
setting/getting parameters
• Improved configuration file
support
• Time stamping for SFN
operation
• Improvements in logging
• FIR filter
• Remote control
• Running on Odroid U3
(Galaxy S3 ARM phone chip)
To be done:
• Test DLS and Slideshow • Configuration ‘app’ to make
setup easier
• Experimental EDI output
• Configuration ‘app’ to make
setup easier
• Experimental EDI output
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12. Technical work we plan to do
• Frequency planning
• Single frequency network operation
• Further software development
• Field testing
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13. What you’ll see today
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Mask filterPower
amplifier
Software
defined radio
Encoding,
multiplexing
& modulator
Transmitting
antenna
Feeder
cable
Single
transmitter
Audio x n
Mask filterOn-channel
repeater
Transmitting
antenna
Feeder
cable
On-channel
repeater
Off-air signal
Satellite fed
gap filler
Mask filterPower
amplifier
Software
defined radioOdroid
Satellite
receiver

14. Trial licensing
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15. Consultation proposals
• Three trials:
– Single transmitter
– Two transmitter SFN
– Two transmitter SFN with one an
on-channel repeater
• Applicants need to identify suitable
transmission sites and at least one
other service provider to be carried in
their trial multiplex
• Ofcom can provide equipment,
although licensees will be able to use
their own
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16. Next steps
• Consultation on small scale DAB trial licensing closes 10 December
• We plan to publish a statement and invite applications during Q1 of 2015
• Trials would run from mid-2015 to March 2016
• Separately, we are giving further thought to a licensing framework
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17. Questions?
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