Larry Irving, Assistant Secretary
for Communications and Information, and
Administrator, National Telecommunications
and Information Administration
The availability of radio spectrum in the United States is critical to many telecommunications services, ranging from cellular telephones to air traffic control. Although spectrum is not a consumable resource, the use of a frequency at a given location usually excludes that frequency from being used by others in the same geographic area. This need for exclusive geographic use has led to current spectrum regulations that establish exclusivity in spectrum use by granting licenses for spectrum use, and the partitioning of the spectrum for shared use between radio services.
As the number of spectrum users increases, the amount of spectrum available for new and existing services decreases. Thus, to successfully plan for tomorrow's spectrum use, the spectrum management community must have an understanding of expected future spectrum requirements and spectrum availability, as well as the potential effects of new technology on the efficient use of the spectrum. A long-term spectrum plan can then be developed and used to guide modification of spectrum allocations, standards, and channeling plans for the best mix of radio services, economy, and spectrum efficiency.
The National Telecommunications and Information Administration (NTIA) is the primary Federal agency working toward the definition and development of the National Information Infrastructure (NII), commonly referred to as "the information superhighway." The NII will be a network linking people, businesses, schools, hospitals, communities and governments, allowing them to communicate and exchange information using voice, video and data with computers, telephones, radios, and other devices. The concept of the NII encompasses a wide range of telecommunications equipment, services, and transmission media. The technology encompassed by the NII includes, among other things, electronic cameras, computers, televisions, optical fiber transmission lines, microwave links, satellite systems, wireless networks, car telephones, pagers and facsimile machines. The NII will integrate and interconnect these physical components to provide a nation-wide information conduit, accessible by everyone. Although the NII is not a discrete telecommunication service, the increase in information flow, particularly to and from mobile users, will ultimately result in an increased requirement for radio spectrum to support the various mobile and fixed service interconnections.
Recently, commercial demand for access to some segments of the radio spectrum has exceeded spectrum availability in many major U.S. markets. Leading the demand for additional spectrum allocations are the various high-technology mobile systems, such as personal communications services (PCS), mobile-satellite systems interconnecting to the public switched telephone network (PSTN), enhanced public safety systems, and a variety of wireless data and voice systems. The continued growth of the telecommunications industry depends to a significant degree on the effective allocation of spectrum to meet additional radiocommunications requirements.
The Federal Government has unique requirements for spectrum use to support the many and varied missions of the Federal agencies. Most of the Federal spectrum use is in support of unique missions that are of direct benefit to U. S. citizens, such as Federal law enforcement, air traffic control, national defense, weather services, and environmental monitoring. Recognizing that continued economic growth in the telecommunications industry and other businesses is dependent on adequate spectrum to support new radiocommunications systems, the future use of the spectrum must be carefully planned so it can adequately support both commercial interests and the critical missions of the Federal Agencies.
To address the issue of spectrum planning, the Congress directed NTIA to prepare a long-term, strategic spectrum plan. The Congress also directed NTIA to meet biannually with the Federal Communications Commission (FCC) to discuss strategic spectrum planning and other key radio issues. The development of a realistic and dynamic spectrum plan requires periodic evaluation of spectrum requirements, analysis of spectrum availability, and preparation of spectrum planning options. Spectrum plans require periodic revisions because of the dynamics of spectrum management actions, fueled by new technologies and market demands.
NTIA's Strategic Spectrum Planning Program is divided into three phases: (1) Definition of long-term spectrum requirements, (2) spectrum availability and planning options, and (3) spectrum allocation implementation plans. As the first phase of this planning effort, NTIA issued a Notice of Inquiry (Notice) in June 1992, requesting comments from both the private sector and Federal agencies regarding future spectrum requirements. The Notice also requested information on future technology, technology trends, and international radio conference preparations. The purpose of this inquiry was to gather information for use in the long-term spectrum planning process. NTIA also conducted long-term spectrum studies to define critical radio service requirements. This report completes Phase 1 of the program. Phase 2, the spectrum availability report, is expected to be completed approximately one year from the date of this report.
This report describes a 10-year projection of spectrum requirements needed to support evolving radiocommunications requirements in the United States, based on the comments to our Inquiry, the NTIA studies, and other available literature. This report describes the present and projected uses of spectrum within the United States for all licensed radio services. Requirements for unlicensed radio services are not addressed. The projected spectrum requirements will need to be periodically re-evaluated as technology and needs change. The projected requirements not only serve as a key input to the long-term planning process, but are also intended to elicit comments concerning the validity of the requirements and the inter- relationship between the needs of the various radio services. This will ensure that evolving requirements will be balanced and will benefit from a broad range of discussions. It will be a significant challenge over the next few years to develop an efficient, effective and balanced long-term plan, and then a more significant challenge to make allocation or other spectrum management changes to satisfy the requirements.
The conclusions and recommendations contained in this report are those of NTIA. This report has been informally reviewed by the NTIA Interdepartment Radio Advisory Committee, the NTIA Spectrum Planning and Policy Advisory Committee and the Federal Communications Commission. Review of this report by these entities does not necessarily imply their endorsement of the conclusions or recommendations contained herein.
The following table lists the additional U.S. spectrum requirements for both Federal and non-Federal users. The additional spectrum requirements problem may be solved through technical, operational, or allocation changes that include Federal and non-Federal exclusive or shared spectrum, and will be discussed in the next report. The table is followed by a summary of spectrum requirements for radio services, spectrum sharing aspects, technology and technology trends, and comments regarding U.S. preparations for international radiocommunication conferences.
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Table: Summary of Additional U.S. Spectrum Requirements
(10-Year Projection)
=================================================================
Radio Services | Spectrum
Discussed in Part I | Requirements
----------------------------------------------------------------
Land Mobile |
a) Conventional dispatch, public | a) 119 MHz Additional
safety, cellular, PCS, trunked | below 5 GHz.
mobile, and paging |
|
b) Intelligent Transportation | b) 75 MHz below 10 GHz &
System 10 MHz between 10-100
GHz
----------------------------------------------------------------
Aeronautical Mobile | 30 kHz Additional (HF) for
| off-route (OR) and 108 kHz
| for route (R). 100 kHz
| Additional (HF) allocated
| to the Mobile Service.
_________________________________________________________________
Maritime Mobile | 36-60 kHz Additional (HF)
_________________________________________________________________
Mobile-Satellite | 60 MHz Additional
_________________________________________________________________
Fixed | Up To 250 MHz Reduction
_________________________________________________________________
Fixed-Satellite | 200-400 MHz Additional
| (Feeder Links)
_________________________________________________________________
Broadcasting | 1,900 kHz Additional (HF)
_________________________________________________________________
Broadcasting-Satellite | Present Spectrum Adequate
_________________________________________________________________
Radionavigation | Present Spectrum Adequate -
---------------------------------------------------------------
Radiolocation | Present Spectrum Adequate
----------------------------------------------------------------
Radiodetermination-Satellite | Present Spectrum Adequate -
--------------------------------------------------------------
Inter-Satellite | Present Spectrum Adequate
---------------------------------------------------------------
Space Operation | Present Spectrum Adequate
---------------------------------------------------------------
Space Services | Present Spectrum Adequate
---------------------------------------------------------------
Radio Astronomy | 9.6 MHz Additional
| (see note)
---------------------------------------------------------------
Amateur and Amateur-Satellite | 2,180 kHz Additional
---------------------------------------------------------------
Standard Frequency and Time Signal | Present Spectrum Adequate
---------------------------------------------------------------
Meteorological Aids | Present Spectrum Adequate
---------------------------------------------------------------
Note: The radio astronomy community also requested access to an
additional 231 MHz, which could be obtained on a local,
coordinated basis.
=================================================================
Mobile and Mobile-Satellite Services
Land Mobile Services
The land mobile service encompasses all terrestrial mobile operations other than aeronautical and maritime mobile. Land mobile services, including public safety operations, are receiving high visibility in the United States. Numerous proceedings by NTIA and the FCC on land mobile issues, e.g., refarming, PCS spectrum allocations, and studies undertaken by NTIA indicate the importance of this radio service.
The land mobile services, including various public safety operations, are perhaps first among the radiocommunication services in need of additional spectrum within 10 years. This is largely due to the rapid growth in non-dispatch systems, such as cellular radiotelephones and pagers, and the projected growth of PCS and public safety operations. However, spectrum requirements are difficult to individually quantify for each of the service types since many users may show no preference in using services such as cellular or PCS as long as service offerings and costs are competitive.
An estimate of additional spectrum needed for the land mobile services was developed that included projected service needs, the effects of new technology, and the conversion rates of current systems to newer, more efficient technology. In the analysis of spectrum requirements, it was assumed that several of the mobile services are substitutes for each other (for example, cellular telephone, enhanced special mobile radio service and some PCS voice services may be similar). Therefore, since this commonality of telecommunications offerings tends to blur the distinctions between discrete services, the spectrum estimate for land mobile services is presented based on an aggregate user base, rather than on individual service offerings. The total spectrum requirement for these services is estimated to be an additional 119 MHz below 5 GHz.
The Intelligent Transportation System (ITS, formerly known as the Intelligent Vehicle Highway System or IVHS) is an emerging new development in the land mobile service. The ITS, being developed by the Department of Transportation, will employ various types of radiocommunications systems within different radio services aimed at providing for a safer and more efficient future transportation infrastructure. The next five years will see the research and development, evaluation, and operational testing of various ITS projects applying modern communications, location, and control technologies. The Department of Transportation and its advisory committee, the Intelligent Transportation Society of America (ITS AMERICA), have indicated that additional spectrum will be required. Current estimates for ITS spectrum requirements include both radiocommunications services and radar. Preliminary estimates for radiocommunications requirements are for access to 75 MHz below 10 GHz, and 10 MHz between 10 GHz and 100 GHz, as shown in the preceding table. ITS also has additional spectrum requirements for collision-avoidance radar systems, that can be accommodated in current radiolocation bands.
The total expected spectrum requirement for the land mobile services, including ITS, is 204 MHz of additional spectrum in the next 10 years. This is in addition to the recent FCC spectrum allocation of 140 MHz for licensed and unlicensed PCS services. The 10-year requirement for the land mobile services could vary significantly from the estimate because of possible variances in the application of new technology and the timing of conversion of existing systems to new technology.
Aeronautical and Maritime Mobile Services
Two events are taking place within the aeronautical and maritime mobile communities that will help accommodate the expected growth in these services. The first is the implementation of satellite-based communications to fulfill future operational requirements. The second is the migration to more efficient technologies. The aeronautical community is considering implementation of either a reduction of channel bandwidth to 8.33 kHz, or a time-division multiple access system for future air-ground systems, and the maritime mobile community is planning to narrowband their VHF allocations to alleviate spectrum congestion. Further, much of the aeronautical voice traffic will be replaced by more efficient computer-to-computer data links that transmit aircraft flight information, such as estimated time of arrival, landing clearance, and weather information between ground and aircraft computers.
Requirements for an additional 30 kHz and 36-60 kHz have been identified for the aeronautical (OR) and maritime mobile services, respectively. There is also a requirement for an additional 108 kHz for the aeronautical mobile (R) service, and 100 kHz in the mobile service to support aircraft operations.
Mobile-Satellite Services
Expected demand for the mobile-satellite service (MSS) will require approximately 60 MHz of additional spectrum, particularly for MSS service to hand-held terminals. This requirement is in addition to the spectrum allocated in the United States today for MSS in the 1.5-1.6 and 2.4 GHz bands for service links for communications to the MSS subscriber equipment. MSS systems also require spectrum for communicating between the satellite and large earth stations to complete the communications path. The communications links to these large fixed earth stations are known as feeder links. Feeder links are considered to be a fixed- satellite service (FSS) application. Spectrum requirements for feeder links are discussed in the fixed-satellite section.
It is noted that of the 80 MHz of spectrum the FCC presently has in reserve for emerging technologies, 30 MHz is aligned with the 1992 World Administrative Radio Conference (WARC-92) worldwide MSS allocations and may become available in the future for MSS operations in the United States.
Fixed and Fixed-Satellite Services
Fixed Service
The continuing replacement of microwave links by optical fiber is the most important factor affecting spectrum requirements for the fixed service. The use of microwave for general common carrier service has decreased substantially. As a result, the number of licenses in the 4 GHz band has decreased by 35 percent in the past five years. It is estimated that the 4 GHz band could accommodate the remaining users with 250 MHz less spectrum within 10 years.
The use of microwave links to connect rapidly growing cellular networks has caused growth in the 2 GHz, 6 GHz, and 11 GHz common carrier bands. However, the continued increase in the use of optical fiber and the capability of currently-installed copper wire to carry high bit-rate information may, in the long-term, cause the aggregate number of licenses in these bands to decrease.
Following years of rapid growth, the use of microwave links by the cable TV relay service in the 13 GHz band has been relatively stable during the past two years. The number of licenses is expected to decrease in the next five years. However, private operational microwave is expected to grow three percent over the next 10 years, in applications where fiber is too expensive or is impractical to install.
In general, there is potential for growth in fixed microwave usage in frequency bands above 15 GHz. These bands are currently less used than the lower frequency fixed bands, and are suitable for short links connecting cellular and PCS cell sites. Many of the users in the 2 GHz band displaced by PCS applicants may be reaccommodated in these bands.
Although some common carrier bands are growing now, it is expected that the aggregate number of fixed service licenses in the 4 GHz, 6 GHz, and 11 GHz bands will decrease over the next 10 years. The 6 GHz band, although currently showing growth, is expected to decrease in the future.
The Federal Government's use of fixed microwave links is similar in many respects to that of the private sector. Federal use of these fixed systems shows a slow but steady growth. Improved spectral efficiency of new systems and conversion of existing systems to new technology will permit the current Federal fixed allocations to be adequate for the 10-year period. Any special spectrum needs, including systems having the high level of reliability, availability and security required by some Federal Agencies, will continue to be accommodated by the present allocations. This includes the expanded use of military transportable systems operating in the fixed service bands. Military use of spectrum supporting transportable fixed systems is necessary to maintain effective command and control capabilities. These systems are used in the United States for training and for communications in disaster relief operations.
If new large-scale fixed systems are built in support of PCS, they are expected to be established in the higher fixed bands. Excluding PCS-related systems, the total number of point-to-point microwave systems is expected to remain constant or decrease slowly.
Fixed-Satellite Service
The conventional FSS should be adequately served by its present spectrum allocation for the near future. Satellites may continue to be the best choice for point-to-multipoint applications, while terrestrial systems (mainly optical fiber) would capture more of the point-to-point market. Spectrum made available by technological developments, such as video compression, may be absorbed by the requirements for additional video program distribution created by the falling cost of fiber optic equipment used for distribution. The FSS will also continue to provide a backup capability for systems using optical fiber, submarine cable, and terrestrial microwave.
Feeder links for geostationary MSS systems may be accommodated in bands currently allocated to the FSS. However, approximately 200-400 MHz of new FSS spectrum allocations may be required to accommodate non-geostationary MSS feeder links, because these feeder links cannot share in all cases with conventional FSS systems. Sharing with some types of terrestrial systems, however, appears feasible. MSS feeder links will require a total of more than 1 GHz of spectrum.
Broadcasting and Broadcasting-Satellite Services
The U.S. leadership in implementing digital signal processing and video compression technology in the broadcast services suggests that the United States will remain competitive internationally in providing digital audio broadcasting and high- definition television (HDTV) technology. Efforts to develop and implement digital audio radio for AM/FM radio broadcasting and HDTV for television broadcasting in their presently allocated frequency bands appear promising. No additional spectrum appears necessary for terrestrial AM, FM, and TV broadcasting. The eventual implementation of HDTV in the UHF-TV channels may free some, if not all, of the 72 MHz presently allocated to VHF television. Although this is not expected to occur within the next 10 years, considerable debate and competition can be expected between broadcasters and other potential users on how this spectrum should be used.
High-power, direct broadcast satellites (DBS) have come into operation in the broadcasting-satellite service (BSS) to provide television programming direct-to-the-home. The first U.S. DBS satellite has been launched and service has begun in most areas. The spectrum planned to support DBS and BSS-HDTV is sufficient and no additional spectrum appears to be necessary.
BSS (sound) systems are under development in the United States. These systems are expected to employ digital technology to broadcast compact disc (CD) quality programming to consumers' mobile or portable radios anywhere in the United States. The spectrum recently allocated for BSS-sound appears adequate for the foreseeable future.
High frequency broadcasters continue to express a strong need for increased spectrum allocations. Both Federal and non-Federal HF broadcasters identified their requirements as the spectrum shortfall resulting from the WARC-92. This shortfall amounted to approximately 1,900 kHz of internationally allocated spectrum.
Radionavigation
There is a trend toward the use of satellite-based technologies for both aeronautical and maritime radionavigation services. An example of this trend is the eventual replacement of LORAN-C by satellite-based navigation systems, such as the Global Positioning System (GPS). The GPS is expected to replace some radionavigation systems currently used in the aeronautical, maritime, and land transportation industries. For example, replacement of the VHF/UHF Instrument Landing System (ILS) by GPS-based systems is under consideration. The GPS is also considered by the International Civil Aviation Organization as a vital part of any future global, long-range, satellite-based navigation system. However, large-scale replacement of aircraft landing systems will take many years, and terrestrially-based systems may be needed as backup while confidence builds in satellite-based systems. In view of this future replacement, radionavigation spectrum allocations, including those for non- military radars, appear adequate for the next 10 years. However, they may be reduced as GPS-based systems replace current systems.
Radiolocation
The primary use of the radiolocation service in the United States is for military radars. The concept-to-deployment cycle of a major new military radar system is typically 15-20 years. Once radars are deployed, they are usually used for at least 10 years. There is a trend toward keeping older radars operational for 20 years or more by modernizing the electronics and signal processing rather than funding a completely new design. Although there are radiolocation requirements for radar systems in the HF and VHF spectrum range, these systems are designed to share the spectrum with existing users, and new allocations may not be required.
Extensive research and development is being focused on ultra- wideband (impulse) radars. Although long-term spectrum requirements may evolve if these systems become operational, special arrangements will have to be developed regarding their allocation status because the necessary bandwidths would overlap numerous bands allocated to other services.
ITS collision-avoidance radars may require access to up to 220 MHz in the bands above 10 GHz. It is expected that these systems will be low-powered, and be accommodated in existing allocations.
Thus, taking into consideration the life cycles of existing operational radars, the trends, and the on-going research and development activity, the long-term radiolocation service spectrum requirements can be accommodated within the existing allocations.
Other Space Services and Radio Astronomy
Space communication services represent a wide variety of systems with differing spectrum requirements. Those services involved with tracking, telemetry and command (TT&C) functions and Federal launch facilities have adequate spectrum. Although there are recent developments in the space research and inter- satellite services, and the emerging commercial launch facilities, these will not require additional spectrum in the next 10 years.
Services primarily involved with the remote sensing of earth and space also have varied spectrum requirements. Present allocations for Earth-directed sensing systems appear adequate, but some flexibility in the spectrum management processes may be needed to accommodate unique space systems.
Radio astronomers are seeking access to approximately 239.6 MHz of additional spectrum (9.6 MHz allocated plus 230 MHz locally coordinated) through coordinated sharing and upgraded allocation status, whereas radar astronomers are adequately served for the foreseeable future.
Other Radio Services
Amateur Service
The amateur and amateur-satellite service allocations have been based, in part, on the desirability of having a choice of relatively narrow frequency bands distributed throughout the spectrum with different propagation properties. Current amateur allocations start at 1800 kHz and, in narrow bands, extend to 250 GHz.
The amateur community commenters have suggested significant changes to the allocation table to accommodate expanded amateur operations. Amateurs generally express a desire for retention of the present amateur bands, additional spectrum, and for upgrading certain current amateur allocations. Many of the suggested allocation revisions are reasonable, and aggregate to about 2,180 kHz of additional spectrum. However, the requested co-primary sharing of amateur operation with radars in Federal radiolocation service bands is not feasible because of the potential loss of operational flexibility for military radar systems needed for national defense.
Amateur-Satellite Service
The amateur-satellite service will soon have a new generation of amateur satellites in orbit that will use all frequency bands allocated to the amateur-satellite service from 29 MHz through 24 GHz. For this reason, the retention of current allocations, additional amateur-satellite allocations, and the upgrading of certain current allocations is desirable. Again, the suggested co-primary sharing of amateur operation with radars in Federal radiolocation service bands is not feasible because of the potential loss of operational flexibility for military radar systems.
Standard Frequency and Time Signal Services
The frequency and time reference signals provided by these services (including the standard frequency and time signal- satellite service) are used in association with scientific research, and as standards for Universal Coordinated Time where precise time is required.
The HF and LF standard frequency and time signal services continue to fill important user needs. Mutual interference will likely continue to be a problem for users of HF services in some areas, but alternative sources are becoming more widely available and economically feasible. In the long term, it may become possible to replace some or all of the terrestrial HF and LF services with more reliable satellite-delivered services. Current spectrum allocations for this service are adequate for the next 10 years.
Meteorological Aids Service
Reliance on the meteorological systems operating in the meteorological aids service is continually increasing due to the need for accurate weather predictions, as well for the investigation of worldwide climatological theories such as global warming. Accurate and timely prediction of severe weather helps to minimize loss of life, destruction of property, loss of agricultural production, etc. No additional spectrum appears necessary in the foreseeable future for the meteorological aids service.
Spectrum Sharing
The radio frequency spectrum is required to satisfy current and future needs for both the Federal and non-Federal radiocommunications service users. The spectrum is allocated to 40 radio services as defined in the FCC's Rules, and the Manual of Regulations and Procedures for Federal Radio Frequency Management (the NTIA Manual). With the increased use of frequency bands below 6 GHz, services that cannot find relief by moving to the higher bands must turn to sharing with other services, or to sharing between Federal and non-Federal users. Sharing opportunities for Federal and non-Federal users, particularly in the mobile, fixed, and space science services, should be increased.
NTIA has in the past recommended increased flexibility in spectrum allocations, and studying an interference-limited approach to licensing. Flexibility in spectrum use within a frequency band, along with the use of the most advanced automated frequency selection and assignment systems and the establishment of receiver standards to reduce interference effects, are key elements for increased spectrum efficiency. NTIA recognizes that the development of receiver standards has not always been accepted. However, it is becoming evident that more attention must be directed towards the electromagnetic environment surrounding radio systems. Manufacturers should be encouraged to design receivers that are more compatible with the existing environment and use the spectrum more efficiently. Finally, national spectrum allocations should also provide for flexibility of radio service use, including the use of electromagnetic compatibility techniques, to make the most efficient use of the spectrum.
Recent downsizing of DOD operational units coupled with current demands for global mobility of our military forces, places greater demands on military spectrum planning than ever before. To exacerbate the problem, due to the result of recently enacted legislation, the military services may lose spectrum for which they have primary control. Future military spectrum planning should consider increased spectrum sharing between the military and other spectrum users in non-military frequency bands. Increased access to non-military bands on a synergistic or coordinated basis could increase the flexibility of military spectrum use in the United States.
Radio astronomy observatories require continued protection from interference. Airborne and satellite-based transmitters pose the greatest threat to radio astronomers, but the proliferation of low-powered devices and the advent of ultra-wideband systems are becoming a significant concern.
Co-channel sharing of the UHF television broadcast spectrum by other radio services in the same geographic area is not feasible. However, flexibility in the use of TV spectrum (i.e., ancillary services) may permit more efficient use of the spectrum.
Television receive-only (TVRO) systems are becoming widespread in the United States. Because TVRO systems are mostly unprotected, sharing TVRO with new terrestrial fixed systems has become difficult. Although the total number of fixed systems is decreasing in the 3.7-4 GHz band, if the band will be used for accommodation of some users displaced from the 2 GHz band, the establishment of new fixed links is likely to make TVRO use untenable in some areas.
Technologies
Semiconductor and information processing technologies, augmented by optical fiber and component development, drive important innovations in telecommunications. In particular, the microprocessor control of digitized information has spurred the development and implementation of techniques ranging from signal compression to scanning antenna arrays. Well within the next ten years, it will be possible for a portable transceiver to automatically optimize its performance by altering equipment parameters, such as bandwidth, modulation, and antenna pattern. Such versatility has significant implications for spectrum management in the future. The potential effects that the application of this technology will have on radiocommunications must be studied by the spectrum management community.
The move to spectrum above 10 GHz by the fixed and fixed- satellite services should pose few unanticipated problems despite the increased absorption of the signal because of rain and gaseous atmospheric constituents. Silicon and gallium arsenide appear to be the semiconductor materials that, when used in monolithic microwave integrated circuits, will help to extend radio use into higher frequencies. Experiments should determine if the low link-margin performance of small-aperture earth stations operating at 20 GHz and above is acceptable. Technological innovations provide for spectrum utilization well into the millimeter band.
Advances in digital modulation and microprocessor technology are resulting in spectrum conservation within existing narrowband channels, and the implementation of spectrum-efficient wideband systems. However, technical and regulatory problems will arise when spectrum is shared between ultra-wideband and multiple narrowband systems. Spectrum planning is increasingly aided by innovations in dynamic control of spectrum resources, most notably for frequency selection, bandwidth and transmitter power.
The alteration of an antenna's radiation pattern is becoming a practical tool for spectrum management. The greatest advances appear to be in electronically-phased arrays with real-time programmable capability. For spectrum sharing purposes, antennas capable of changing their center frequency and bandwidth, as well as radiation pattern, need to be further investigated for commercial applications.
More sophisticated propagation models that can handle fixed, mobile, and mobile-satellite systems are required for efficient spectrum management. In particular, the development of wideband models for point-to-point paths within buildings and through walls are a priority for cellular and personal communications system analysis.
U.S. Preparations for International Radio Conferences
Spectrum management has become globalized, and the United States is a critical part of this worldwide radio community. It is increasingly important that the United States develops a more coordinated and global view of radiocommunication services and spectrum allocation issues. To achieve this, the United States must maintain a continuous planning process that addresses advanced telecommunications technologies and worldwide services, and should re-evaluate the process by which domestic spectrum allocations are made, taking into consideration international markets for goods and services.
Many administrations are now in the process of privatizing previously government-owned and operated telecommunications systems. New systems and networks are being planned and established worldwide. Recognizing that these system developers may choose from multiple technologies, the United States must be competitive in international telecommunications markets, offering goods and services that meet common technical standards adopted by various administrations. To facilitate this, the United States must actively participate in international standards-setting activities, and maintain a progressive dialogue with regional administrations concerning spectrum and general telecommunications issues.
Current World Radiocommunication Conferences are held on a regular two-year cycle and may be somewhat narrower in scope than previous radio conferences. The two-year cycle adopted by the International Telecommunication Union (ITU) will make the ITU more responsive to an increasingly dynamic market and telecommunications environment. Furthermore, this new two-year cycle is expected to result in more efficient conference management; both domestically and within the ITU. However, the new two-year conference cycle will require a continuous planning process.
As part of this planning process, the IRAC recently established the Radio Conference Subcommittee (RCS) to develop recommended U.S. proposals and positions for ITU radio conferences. The RCS has established a close liaison with U.S. industry.
To improve the conference planning and preparation process, the head of the U.S. delegation should be appointed early in the two- year conference cycle in order to permit sufficient time to prepare for each conference. To facilitate the process by which the United States prepares for international radio conferences, NTIA will:
Conclusion
This report projects U.S. spectrum requirements for a 10-year period based primarily on technical factors. The process of developing national requirements and forwarding these as U.S. requirements to international conferences requires additional consideration of technical, operational and regulatory factors. Among other factors in the planning process, we must also determine availability of spectrum, and prepare long-term spectrum plans, corresponding to phases 2 and 3 of the Strategic Spectrum Planning Program. These plans will include spectrum options and reallocation trade-offs needed to address future spectrum needs in a coordinated manner.
It has been said that long-range spectrum planning cannot be effectively accomplished. We recognize the many difficulties and problems with long-range planning, but must address the issues so we can make intelligent choices and address necessary changes in a realistic fashion. The alternative is to continue to address each spectrum requirement as it arises on a case-by-case basis, and often in a crisis-mode environment.
The projected spectrum requirements contained in this report are a key input to the long-range planning process. Further, our estimates of spectrum requirements are intended to foster dialogues between spectrum users and regulators, to ensure that spectrum is allocated to satisfy future requirements in a balanced and equitable fashion.
