World Broadcasting Unions Digital Radio User Manual - page 58

DIGITAL RADIO GUIDE

TERRESTRIAL TRANSMISSION SYSTEMS - ISSUES

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4.5

Issues related to Terrestrial Systems

4.5.1

Spectrum Availability

Government policies on frequency management and spectrum pricing affect all radio

broadcasting development.  In some countries the radio spectrum is looked upon as a

means of raising revenue.

Administrations in different countries operate different policies, but there are common

threads. Whether frequencies are allocated through auctions or by other means,

spectrum is undeniably a scarce resource and especially so in the bands that are most

useful for digital audio broadcasting (including the existing shortwave bands, existing AM 

and FM bands, as well as the upper VHF and L-Bands).

In many countries administrations have allocated spectrum for digital broadcasting, both

radio and TV.

The DRM system is designed to work within the existing band and channel structure for

all the broadcasting bands below 30 MHz. As such, its use of the spectrum conforms to

the Geneva Treaty of 1975 for ITU-R Regions 1 and 3, the long wave and medium wave 

channels have a 9 kHz bandwidth, or multiples thereof, depending on the channel

assignment; the Rio Treaty of 1981 for Region 2 medium wave specifies a 10 kHz

bandwidth; and the shortwave channel bandwidth is 10 kHz for all the HF broadcasting

bands. Thus, no new spectrum is required. Furthermore, based upon ITU-R decisions

during 2003, DRM signals can be used operationally in these bands, with the existing

channel bandwidths, interspersed with the analogue broadcasts. That is, there are no

specially allocated segments of bands for digital transmissions. Ongoing testing has

verified the feasibility of this approach.

In the US, the government has approved HD Radio as a way to alleviate the need for

new spectrum to implement terrestrial digital radio.

The constraints and uncertainties that cloud the issue of frequency allocations for new

digital terrestrial services in the VHF and L-Bands are not such a problem for AM digital

developments. There is some prospect that the congestion now in the AM bands could

be reduced with digital broadcasting. Potentially, there is much to be gained from digital

broadcasting in the short-wave bands because current analog systems require a number

of simultaneous broadcasts to ensure reliable reception under changing ionospheric

conditions.

Case Study: Allocations in Region 1

In the UK, where spectrum is being allocated for seven Eureka 147 DAB multiplexes, the 

granting of license has been in VHF Band III, which is very suitable for terrestrial DAB (T-

DAB) transmissions.  Across Europe, both VHF and L-Band frequencies will be used for

T-DAB services. At a planning meeting held set up by the CEPT (European Conference

of Postal and Telecommunications Administrations and held in Wiesbaden) in 1995,

frequency blocks in three bands were considered:

•

VHF Band I  (47 – 68 MHz)

•

VHF Band III (174-240 MHz)

•

L-Band (1452 – 1467.5 MHz)

The Wiesbaden plan made allotments for digital audio broadcasting in VHF channels 11

and 12 and in the L-Band, and considered the implications of protecting non-DAB