1. Spectrum Policy Task Force Findings and Recommendations
Dr. Paul J. Kolodzy
Stevens Institute of Technology
Former Director of FCC SPTF
Presentation to the
International Symposium on
Advanced Radio Technologies
March 2003 /

2. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Major Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

3. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Introduction
Task Force has begun process of reexamining 90 years of spectrum policy to ensure that Commission’s policies evolve with the consumer-driven evolution of new wireless technologies, devices, and services.
First ever comprehensive and systematic review of spectrum policy at the FCC.
Team of high-level, multi-disciplinary professional FCC staff – economists, engineers, and attorneys – from across the Commission’s Bureaus and Offices
Catalyst for further advancement of spectrum policy at the FCC. /

4. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Oh, FCC May I …
Increase My Power?
Have Some Spectrum?
Change the Service?
Have Some Spectrum? /

5. Introduction Disclaimer
The Spectrum Policy Task Force Report drafted by FCC staff and was not voted on or approved by the Commission.
Neither the Report nor any of the recommendations contained therein necessarily reflect the views of the Commission. /

6. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Major Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

7. Spectrum Policy Reform: The Time is Now
Increasing demand for spectrum-based services and devices is straining longstanding and outmoded spectrum policies.
Demand propelled by a host of factors:
economy has moved towards communications-intensive service sector
American workforce is increasingly mobile
consumers have been quick to embrace the convenience and increased efficiency of multitude of wireless devices available today
advances in technologies have significantly increased diversity of service offerings and have qualitatively improved existing services and devices, particularly for Internet and wireless data, which can be delivered at faster rates.
businesses and homes with multiple computers growing and users installing local area networks to share resources /

8. Spectrum Policy Reform: The Time is Now
Technological advances are enabling changes in spectrum policy
Technology providing potential answers to current spectrum policy challenges.
increased use of digital technologies
Increase potential throughput of information
Interference management:
digital signals inherently more robust, and resistant to interference, than analog signals
digital signal processing techniques, such as coding and error correction, more effective at rejecting interfering signals
development of software-defined radios
operating parameters in radios (such as operational frequency and modulation type) determined by re-programmable software
also called “smart” or “opportunistic” technologies because, due to their operational flexibility, can search the radio spectrum, sense the environment, and operate in spectrum not in use by others
by operating in “white” – or unused – spaces in the spectrum, can enable better and more intensive use of spectrum /

9. Spectrum Policy Reform: The Time is Now
Increased access can mitigate scarcity of spectrum resource
Most “prime spectrum” has already been assigned to one or more parties, and it is becoming increasingly difficult to find spectrum that can be made available either for new services or to expand existing ones.
Improving access to the spectrum can be achieved through permitting licensees greater flexibility and other means. /

10. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Major Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

11. Major Findings & Recommendations
Technology advances create potential for radio systems to use spectrum more intensively and to be more tolerant of interference.
Implement new paradigm for interference protection
In many bands, spectrum access more significant problem than physical scarcity, in large part due to legacy command-and-control regulation.
Preliminary data and general observations indicate many portions of spectrum not in use for significant periods of time, and spectrum use of “white spaces” (both temporal and geographic) can be increased significantly.
Additional information and measurement needed to more accurately quantify and characterize spectrum usage and availability.
Spectrum policy must evolve towards more flexible and market-oriented regulatory models to increase opportunities for technologically innovative and efficient spectrum use.
Eliminate regulatory barriers to increased spectrum access /

12. Major Findings & Recommendations
Regulatory models must be based on clear definitions of rights and responsibilities of both licensed and unlicensed spectrum users, particularly with respect to interference protection.
No single regulatory model should be applied to all spectrum:
pursue balanced spectrum policy that includes both the granting of exclusive spectrum usage rights through market-based mechanisms and creating open access to spectrum “commons,” with command-and-control regulation used in limited circumstances.
Migrate from current command and control model to more market-oriented exclusive rights model and unlicensed device/commons model
Implement policies in both newly allocated bands and in spectrum that is already occupied, but appropriate transitional mechanisms should be employed to avoid degradation of existing services and uses. /

13. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Major Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

14. Interference Avoidance Recommended Methods of Interference Control
Adopt a more quantitative approach to interference management based on the concept of “interference temperature.”
Interference temperature metric would establish maximum permissible levels of interference, characterizing the “worst case” environment in which a receiver would be expected to operate.
Different threshold levels could be set for each band, geographic region or service -- set only after review of the condition of the RF environment in each band.
systematic study of the RF noise floor necessary
Receiver performance requirements for some bands and services, through incentives, mandates, or some combination of incentives and mandates. /

15. Interference Avoidance
It doesn’t matter what the signal level is here!
Interference
Temperature
It matters what the signal level is here!
One recurring and often thorny issue is how to protect users against harmful interference. Despite the fact that the Commission has had extensive, and generally successful, experience in managing interference issues, these issues have been increasing in technical difficulty and prevalence due to the changing RF environment generated by new devices and new technology. The rules should specify a more accurate measure of interference that takes into account the cumulative summation of all the undesired RF energy available to be captured by a particular receiving antenna for delivery to the receiver. To achieve this objective, as well as to transition interference management to more accurate real-time measurements, the Task Force recommends that the Commission adopt a new metric, “interference temperature,” to quantify and manage interference. The interference temperature measures the RF power available at the receiving antenna per unit bandwidth.
Conceptually, as illustrated this figure, interference temperature measurements would be taken at various receiver locations to estimate the real-time condition of the RF environment. The degree of certainty of the estimate of the environment would depend on such factors as transmitter signal ranges, uniformity of signal levels over an area, the density of temperature measuring devices and the sharing of the data taken by nearby devices; e.g., through “ad hoc cooperative wireless networks.” The Commission could use the interference temperature metric to establish maximum permissible levels of interference, thus characterizing the “worst case” environment in which a receiver would be expected to operate. Different threshold levels could be set for each band, geographic region or service, and these thresholds should be set after the Commission has reviewed the condition of the RF environment in each band.
Define “interference temperature” – total RF energy from both ambient noise and other sources /

16. Interference Avoidance Tolerance of Interference - Today
Licensed signal
Aggregated Signals Reducing Coverage
Design to Original Noise Floor
Power at Receiver
Noise Floor
The Commission’s review of the RF environment should include actual spectrum measurements of the RF noise/interference floor. In addition to obtaining better data regarding the noise floor, the Commission should adopt a standard methodology for measuring the noise floor. Further, the Task Force recommends that the Commission create a public/private partnership for a long-term noise (interference temperature) monitoring network and for the archiving of data, for use by the FCC and the public.
This figure depicts a possible scenario resulting from the current open ended nature of the RF noise floor. A communications system has been designed to operate to a distance from the transmitting antenna at which the signal strength approaches the level of the noise floor that existed when the system was established. Over time, the noise floor can rise unpredictably – this due to additional interfering signals, perhaps including out-of-band emissions from new users and further aggregation of unlicensed devices. As a result, signal coverage can be degraded without warning. Additional interfering signals will progressively worsen coverage.
Current FCC Power Limits
Distance from licensed transmitting antenna
License Holders Design System to Operate down to the Noise Floor
Any additional interfering signals (including aggregation of unlicensed devices) can cause degradation /

17. Interference Avoidance Tolerance of Interference - Future
Prevent Aggregation Above Interference Temperature Limit
New Opportunities for Spectrum Access
Licensed signal
Power at Receiver
Noise Floor
This figure modifies the scenario by placing an interference temperature cap over the service area. Two key benefits will result from the application of the interference temperature metric: First, licensed spectrum users will obtain certainty with regard to the maximum permissible level of aggregated noise, or interference, in their band. The interference temperature would quantify the level of acceptable interference in a particular band. For example, any transmissions from other sources that increase the noise level above the interference temperature would be considered “harmful interference” in accordance with Commission rules. Second, to the extent that the interference temperature in a particular band is not reached, other users (e.g., unlicensed devices) could operate in the same band – with the interference temperature serving as the maximum cap on the potential RF energy they could introduce in the band. This would thus increase access to the band for other users or devices.
Interference temperature sensory and control mechanisms could be used to maintain both in-band and out-of-band emissions within permissible limits. For example, a low power unlicensed RF device could be designed to scan its particular frequency band before transmitting. Its built-in “thermometer” would record interference temperature data and compute the appropriate statistical aggregate value. The device would then project the increase in interference temperature due to its operation over its nominal range. This value would be compared with the permissible limit. If its operation would exceed the limit, the device’s controller could execute an appropriate response such as reducing power, switching to a different transmit frequency (if available) or, perhaps, continuing the scanning/sensing process to locate an opportune time to transmit. The technology now exists to build such sensory control systems. Automated transmitter power control, for instance, is used in certain types of wireless and satellite communications systems. Cordless telephones also adapt to the environment by selecting an unused frequency.
Current FCC Power Limits
Distance from licensed transmitting antenna
Quantify acceptable levels of interference
More Certainty for Licensees
More Opportunity for Consumer Devices /

18. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Major Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

19. Spectrum Usage Models Current State of the Spectrum
Uses & Users Limited by Regulation
High
COMMAND and
Flexible, Market-
Based
Services
Sensitivity to Interference
Medium
MONITOR and
CONTROL
Unlicensed,
Market-
Based
Devices
Low
MARKET
MARKET
Low
Medium
High
“Power” /

20. Spectrum Usage Models Evolve into This
Uses & Users Limited by Regulation
COMMAND and
High
MONITOR and
Flexible, Market-
Based
Services
Sensitivity to Interference
Medium
CONTROL
MARKET
MARKET
Unlicensed,
Market-
Based
Devices
Low
Low
Medium
High
“Power” /

21. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Outline
Introduction
Spectrum Policy Reform: The Time is Now
Overall Findings and Recommendations
Interference Avoidance
Spectrum Usage Models
Promoting Access to Spectrum /

22. Promoting Access to Spectrum Improving Spectrum Efficiency
Access Limited
Throughput Limited
Discourage inefficient use
Improve access through time, frequency, power, bandwidth and space
Group
like systems
Adjust regulations as technology develops
Permit other users or uses --
flexibility
Currently spectrum is access limited
Eventually spectrum may be throughput limited -- not there yet /

23. Promoting Access to Spectrum The New Model
Easement User
2nd-ary
User
Licensee
Not-to-Interfere Basis
Below the Acceptable
“Interference Temperature” /

24. Promoting Access to Spectrum In the Space Dimension
Metro
Area
Rural
Environs
Unlicensed
Devices
2nd-ary
User
License Holder /

25. Promoting Access to Spectrum In All Dimensions
Unlicensed
Devices
2nd-ary
User
License Holder
Sharing
Frequencies
Time &
Spectrum
Low Power
Devices
Licensed
Service Area /

26. Use of public safety spectrum is highly variable
Promoting Access to Spectrum Through Increased Flexibility Illustration: Public Safety & Dynamic Spectrum Use
CMRS
Data Services
Public Safety 1%
10%
100%
Duty Cycle 1%
10%
100%
10% 1%
Data Services
CMRS
Public Safety
Use of public safety spectrum is highly variable /

27. What’s Next? For Advanced Radio Technology Community
Determine Viability of Technology for:
Monitoring Interference Temperature
Benign Environs
Complex Environs
Adaptation Techniques
Opportunistic Spectrum Access
Space
Time
Start Thinking about Wireless Cyber-Security /

28. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu
Thank you!
Questions? /