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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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

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. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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. pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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” pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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” pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

Promoting Access to Spectrum The New Model Easement User 2nd-ary User Licensee Not-to-Interfere Basis Below the Acceptable “Interference Temperature” pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

Promoting Access to Spectrum In the Space Dimension Metro Area Rural Environs Unlicensed Devices 2nd-ary User License Holder pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

Promoting Access to Spectrum In All Dimensions Unlicensed Devices 2nd-ary User License Holder Sharing Frequencies Time & Spectrum Low Power Devices Licensed Service Area pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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 pkolodzy@fcc.gov / pkolodzy@stevens-tech.edu

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