World Broadcasting Unions Digital Radio User Manual - page 20

DIGITAL RADIO GUIDE

TERRESTRIAL TRANSMISSION SYSTEMS - DAB

20

Many ancillary aspects of the Eureka 147 system, such as multimedia delivery,

distribution interfaces and user interactivity are also formally defined in ETSI standards. 

Eureka 147 can be implemented for a range of applications such as wide area or local

delivery of audio and data services for mobile, portable and fixed reception. It can be

delivered terrestrially, via satellite, cable or a mixture of terrestrial and satellite. 

Eureka 147 is designed to be used across a wide spectrum range, from 30 to 3000 MHz, 

but has only been implemented using VHF Band III and the 1452 to 1492 MHz segment

of the L Band.

Eureka 147 uses a wideband COFDM modulation system which provides a robust

transmission which is multi path resilient and can provide high availability coverage.

Eureka 147 can be implemented using on channel repeaters in SFNs or low power gap

fillers and extenders. SFNs may also provide “network gain” giving improved service

availability over single channel services.

Eureka 147 can accommodate a varying number of audio services of differing quality with 

associated data. The audio quality can range from simple mono speech to CD quality. An 

increase in quality requires higher data rates for each audio service, hence reducing the

number of services that can be delivered. Data can also be delivered independently of

the audio services. 

Eureka 147 uses mature technologies such as MPEG 1 Layer II and MPEG 2 Layer II

audio coding systems and COFDM modulation, which are also used in the DVB T video

broadcasting standard. This should lead to cheap single chip solutions for receivers. 

Eureka 147 has been extensively standardised by European standards organisations and

it would be fairly straightforward for these standards to be adopted as Australia standards 

by Standards Australia.

A growing number of Eureka 147 receivers are now available for portable, PCs, mobiles, 

in car and in house reception.

Challenges

The MPEG 1 Layer II and MPEG 2 Layer II audio coding systems are now somewhat

dated (compared with new systems) but they offer excellent robustness against channel

errors due to unequal error protection (UEP). The system allows for inclusion of newer

coding systems as independent data, but DAB receivers would need to be adapted or

replaced to receive these services.

While a wide range of DAB receivers is already available on the market, they are still

generally seen as being too costly for general public acceptance, particularly when

compared to the very cheap AM and FM radios that many listeners currently use.

However, as Eureka 147 services have expanded, the cost of receivers have

considerably dropped in price.

Eureka 147 requires services to be multiplexed together before transmission. All audio

programs and data services in a given Eureka 147 channel will therefore have similar

coverage and reception quality. 

The standard capacity of Eureka 147 multiplexes means that conversion would require

existing services to be grouped into blocks of 6 or more services per multiplex, all of

which would then cover the same area. In a conversion model, this would pose