Digital Audio Broadcasting Systems and Their Impact on the Terrestrial Radio Broadcast Service

FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 73

[MM Docket No. 99-325; FCC 99-327]

Digital Audio Broadcasting Systems and Their Impact on the

Terrestrial Radio Broadcast Service

AGENCY: Federal Communications Commission.

ACTION: Notice of proposed rulemaking.

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SUMMARY: In this document, the Commission considers alternative

approaches to introduce Digital Audio Broadcasting (DAB) to the

American public. This document is intended to help the Commission

determine whether an in-band, on-channel (IBOC) model or a model

utilizing new spectrum would be the best means to promptly introduce

DAB service. This document intends to foster development of both

models, help DAB system proponents identify design issues, and

encourage modifications to advance Commission's policy objectives. This

document is in response to USA Digital Radio's (USADR) Petition for

rulemaking, which requested initiation of a proceeding to implement

IBOC DAB technology.

DATES: Comments are due on or before January 24, 2000, and reply

comments are due on or before February 22, 2000.

ADDRESSES: Parties who choose to file comments by paper should address

their comments to Magalie Roman Salas, Office of the Secretary, TW-

A306, Federal Communications Commission, 445 12th Street, SW.,

Washington, DC 20554 and should also submit comments on 3.5 inch

diskette using Microsoft Word or compatible software addressed to

William J. Scher, Federal Communications Commission, 445 12th Street,

SW., Room 2-A445, Washington, DC 20554. Electronic comments may also be

submitted using the Commission's electronic comment filing system via

the Internet to http://www.fcc.gov/e-file/ecfs.html>.

FOR FURTHER INFORMATION CONTACT: Peter Doyle or William Scher at (202)

418-2780 or [email protected] or [email protected].

SUPPLEMENTARY INFORMATION:

1. IBOC DAB. IBOC systems allow simultaneous broadcast of analog

and digital radio signals in the AM and FM bands without disruption to

existing analog service. IBOC DAB systems have not been conclusively

proven to be technically viable, but recent advances hold real promise.

In the hybrid operational mode, IBOC systems transmit lower power

digital signal sidebands positioned on either side of the host analog

signal. Digital signals would be interleaved (station A's upper digital

sideband would be between 1st adjacent channel station B's lower and

upper digital sidebands, and adjoining station B's carrier frequency).

The presence of digital sidebands would reduce the separation between

the host analog signal and 2nd and 3rd adjacent channel digital

signals. IBOC proponents believe digital signal processing techniques

will permit transmission of a digital ``pair'' of each analog signal in

the AM and FM bands, without disrupting existing analog service.

2. In the IBOC all-digital mode, the system proposed by USADR would

continue to divide the digital signal into sidebands, boost power by

tenfold, and use the channel center for lower-power auxiliary services.

The increased power of the signal sidebands likely would interfere with

1st adjacent channel analog signals. Therefore, USADR proposes to use

the hybrid mode for 12 years and then sunset protection of analog

signals. At that time, it proposes to implement the all digital mode.

The system proposed by Lucent Technologies (``Lucent'') consolidates

the digital signal in the channel center in the all-digital mode, and

proposes to use the 1st adjacent for auxiliary services. No sunset of

protection for analog signals would be necessary because Lucent's model

conforms to the Commission's current analog technical rules.

3. DAB Public Policy Objectives. In this Notice, the Commission's

public policy objectives to introduce DAB are (1) to provide vastly

improved radio service to the public, (2) to permit broadcasters and

listeners to realize fully the superior technical performance

capabilities of DAB; (3) to support a vibrant and vital terrestrial

radio service for the public and create DAB opportunities for existing

radio broadcasters; (4) to ensure that the introduction of DAB does not

weaken the vitality of our free, over-the-air radio broadcast service;

(5) to provide all broadcasters with the opportunity to provide DAB

service. The Commission will favor systems that are spectrum efficient,

that do not require burdensome investments in new broadcast

transmission equipment, and that provide broadcasters with incentives

to convert to DAB.

4. Tentative Selection Criteria. The Commission proposes to apply

the following evaluative criteria to determine which DAB model and/or

system would best promote the public policy objectives: (1) enhanced

audio fidelity; (2) robustness to interference and other signal

impairments; (3) compatibility with existing analog service; (4)

spectrum efficiency; (5) flexibility; (6) auxiliary capacity; (7)

extensibility; (8) accommodation for existing broadcasters; (9)

coverage; and (10) implementation costs/affordability of equipment.

5. Enhanced Audio Fidelity/ Robustness. DAB system proponents

anticipate that AM IBOC DAB systems will offer sound quality comparable

to today's stereo FM systems, and that FM IBOC DAB systems will deliver

near-CD quality sound. As to robustness, DAB systems may improve

reception by using techniques that protect digital signals from

interference that affects analog signals. The Commission seeks comment

of these selection criteria, including the specific standards that

should be used to compare competing systems.

6. A comparison of IBOC and new-spectrum alternatives must consider

the time frame to achieve all-digital operations and short-term

performance advantages of a hybrid IBOC system over analog. The

Commission seeks comment on the issue. The Commission also seeks

comment on appropriate ways to compare IBOC and new-spectrum DAB

alternatives under this selection criteria.

7. Compatibility. The Commission tentatively concludes that IBOC

systems should minimize interference to host and adjacent-channel

analog signals in hybrid mode including interference to FM subcarriers.

The opportunity to introduce new ancillary services is tied to

initiation of all-digital operations. A system which permits rapid

implementation to all-digital radio service (such as Lucent's) may

serve the public interest better than a system which relies on a longer

transition period with a fixed sunset of analog protection (such as

USADR's). The Commission seeks comment on whether all-digital

compatibility with analog signals should be an evaluative criteria for

IBOC systems.

8. The Commission seeks comment on how a DAB system could be

designed to protect a possible future LPFM service. The Commission

seeks comment on the

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potential for enhancing the robustness of IBOC systems to reject

undesired 2nd and 3rd adjacent channel signals and the likely impact on

such modifications.

9. Spectrum Efficiency. Spectrum efficiency considers not only

whether a DAB technology would not require additional spectrum, but

also the additional value that results from the transition from analog

to digital transmission service. The added value of spectrum is the

product of several factors, including the capacity to transmit greater

data per hertz, enhanced flexibility, the lesser likelihood of digital

signals to cause interference, less susceptibility to interference, and

more robust with respect to multi-path fading and non-radio noise

sources, and the capacity to provide a listenable service at relatively

low signal strength levels. The Commission wants to examine if digital

receivers could provide additional protection against interference.

What would the cost be to consumers and, besides cost, are there other

considerations?

10. The Commission seeks comment on possible DAB efficiency

standards. Are any of the Eureka-147 and/or satellite DARS signal

bandwidth and interference protection standards relevant in

establishing DAB spectrum efficiency standards? What bandwidth is

necessary for CD-quality signals? What are the spectrum implications of

recent advances in coding and multistreaming technologies? What are the

quantifiable trade-offs between bandwidth and signal robustness? What

trade-offs should the Commission consider in balancing the needs of

incumbents and new entrants? Should there be different data capacity

criteria during and after transition? Would transition be slowed if

incumbents were assigned less bandwidth for all digital operations? Is

preserving (or expanding) bandwidth assignments necessary?

11. Flexibility/auxiliary capacity. The Commission tentatively

concludes that ancillary services must not technically impair reception

of DAB programming. The Commission seeks comment on whether the Digital

Television (DTV) framework is appropriate for radio and what limits if

any, the Commission should establish for ancillary services.

12. Extensibility. The Commission tentatively concludes that

extensibility (ability of a DAB system to adapt to future technological

advances) is crucial to preserving of free broadcast in a digital

environment and ensuring that listeners fully benefit from DAB. The

Commission seeks comment.

13. Accommodation. The Commission tentatively concludes that a DAB

system should, to the maximum extent possible, accommodate all existing

broadcasters wanting to initiate DAB and that placing AM and FM on

equal footing is not essential. The Commission seeks comment.

14. Coverage. Broadcasters argue that a DAB system should be able

to replicate existing coverage areas, which tend to be greater than

``interference-free'' areas protected under Commission's rules. While

the Commission recognizes that preserving existing coverage areas may

be important, it tentatively concludes that the public interest is best

served by a digital assignment policy based on analog protected service

contours. Service contours reflect a balance between providing adequate

service areas and expanding the number of station assignments. The

Commission requests comment.

15. IBOC DAB Model. The Commission believes that IBOC would be

superior to a new spectrum model because it would not require new

spectrum, it would permit a fast transition to DAB while preserving

benefits of analog service, and may achieve certain spectrum

efficiencies. To ensure a smooth initiation to DAB, the Commission

tentatively concludes that if IBOC is adopted, IBOC DAB licenses will

not count as distinct authorizations for purposes of local ownership

rules and seeks comment on that view.

16. The Commission seeks comment on the spectrum efficiency

concerns inherent in the IBOC model and whether a model proposing to

switch digital audio transmission from sidebands to a center band in

the all digital mode would be more spectrally efficient than one which

continues to carry the main audio signal in digital sidebands. The

proposed IBOC systems would double the bandwidth licensed to AM and FM

stations to 20 kHz and 400 kHz respectively, spectrum which is

currently included in analog ``emission masks'' and the Commission

seeks comment on whether spectrum may be returned at the end of the

licensees' IBOC transition to an all-digital operating environment. The

Commission seeks comment on how to balance the need to provide

broadcasters with sufficient incentive to transition rapidly to DAB

with the need to respond to unmet demand for new entrants. The

Commission seeks analyses of minimum power levels needed to preserve

service within protective service areas in a digital environment, and

alternatively, the levels that would result in significant disruption

to current listening patterns.

17. New Spectrum DAB Model. As an alternative to IBOC, the

Commission requests comment on whether the six MHz of spectrum at 82-88

MHz (now TV Ch. 6) could be reallocated to DAB at the end of the DTV

transition. The Commission seeks comment on any possible adverse

affects on DTV implementation and television service in general. The

earliest the spectrum could be available is 2007; however, the

availability of this spectrum is tied to the end of the DTV transition

period and could be significantly later. The Commission requests

comment on all aspects of the new spectrum option and asks whether

there are other frequency bands to consider. IBOC and new spectrum

options are not mutually exclusive and could be complementary.

18. The Commission seeks comment on whether new spectrum models,

which are independent of the existing analog AM and FM radio systems,

would provide greater flexibility to plan and implement DAB, and

whether compared to IBOC in hybrid mode, it would operate at a higher

data rate and support higher audio quality and enhanced ancillary

services. At the time when an 82-88 MHz DAB system proves successful,

analog stations licensed to frequencies in the existing 88-108 MHz

could convert to DAB. The transition could result in significant

service disruptions, unless listeners have digital receivers. The

Commission seeks comment on such transition issues.

19. The Commission seeks comment on whether to maintain the same

channel bandwidth assignment scheme currently used with FM service and

if this approach would facilitate conversion to DAB and a common FM/DAB

radio receiver design in the 82-108 MHz band. The Commission seeks

comment on whether to adopt a consistent service area approach which

follows the plan of existing classes of FM stations (Class A, B1, B,

C3, C2, C1 and C) or should all DAB stations be provided a common

service area?

20. The Commission seeks comment on whether all AM and FM

broadcasters should be eligible for a DAB license, whether DAB licenses

should be excluded from local ownership limits and whether new channels

should be reserved for educational use and new entrants. The Commission

seeks comment on whether it should limit the number of DAB licenses in

each market and whether issuing DAB licenses would implicate statutory

auction requirements.

21. The Commission seeks comment on whether to allot DAB channels

to communities in proportion to the

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number of AM and FM channels operating or based on initial expression

of interest by applicants, and whether either approach is consistent

with 47 U.S.C. 307(b). The Commission requests comment on whether to

use minimum geographic spacing distances or other engineering criteria

to assess technical acceptability of new DAB allotments and

modifications.

22. The Commission seeks comment on whether Channel 6 should be

used to ensure adequate new entrant DAB opportunities and whether the

Commission may give preferences to LPFM licensees in assigning Channel

6 spectrum, and if so, whether it should do so.

23. DAB Transmission Standard. The Commission tentatively concludes

that it is in the public interest for the Commission to take a role in

DAB standards development with the advice and involvement of all

sectors of the industry. The Commission seeks comment on how likely the

broadcast industry is to establish a de facto standard without

Commission action and whether there is anything the Commission can do

short of mandating a standard to assist the industry? The Commission

lacks sufficient information at this time to conclude that a

Commission-mandated transmission standard is necessary and seeks

comment on whether a single mandated standard is desirable. The

Commission seeks comment on whether there is a high degree of

compatibility among the several DAB systems. It also seeks comment on

whether developments in digital signal processors (DSPs) and DSP chip

technology make a standard unnecessary, whether an ``open

architecture'' approach is feasible, and what impact such an approach

would have on the development and costs of receivers.

24. Models for IBOC DAB System Testing and Evaluation. The

Commission believes that it is necessary to rely to some degree on the

expertise of the private sector for DAB system evaluations and

ultimately, recommendations for a transmission standard. However, it

believes it is premature to select an approach at this time. The NRSC

has set a deadline of December 15, 1999 for proponents to submit system

test results and the Commission requests that the parties also submit

the reports to the Commission as part of this proceeding. The

Commission would give great weight to a fair and thorough NRSC testing

process and any industry consensus the NRSC may achieve. However, the

Commission will act promptly to provide an alternative mechanism if the

current process breaks down. The Commission will revisit the

effectiveness of the NRSC approach once the Commission reviews the NRSC

report on IBOC tests expected the first quarter of 2000. The Commission

seeks comment on evaluative models.

25. Initial Regulatory Flexibility Analysis. The Commission has

prepared an Initial Regulatory Flexibility Analysis of the possible

significant economic impact on small entities by the policies and rules

proposed in this Notice. Comments are requested on this IRFA and must

be identified as responses to the IRFA. The proposed rules and policies

potentially will apply to all AM and FM radio broadcasting licensees

and potential licensees. The SBA defines a radio broadcasting station

that has no more than $5 million in annual receipts as a small

business. A radio broadcasting station is an establishment primarily

engaged in broadcasting aural programs by radio to the public,

including commercial, religious, educational, and other radio stations.

As of December 31, 1998, official Commission records indicate that

12,472 radio stations were operating, of which 4,793 were AM stations.

Thus, the proposed rules will affect 12,472 radio stations, 11,973 of

which are small businesses. These estimates may overstate the number of

small entities since the revenue figures on which they are based do not

include or aggregate revenues from non-radio affiliated companies. In

addition, any entity that seeks or desires to obtain a DAB license may

be affected by the proposals. The number of entities that seek to

obtain a DAB radio broadcast license is unknown. The Commission invites

comment on such number. The Notice sets forth policy objectives and

proposes criteria for the selection of alternative DAB models and/or

systems that will promote the interests of small entities and minimize

the economic impact on such entities of a transition to DAB service.

Federal Communications Commission.

Magalie Roman Salas,

Secretary.

[FR Doc. 99-29270 Filed 11-8-99; 8:45 am]

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