# Presentation: 150915

## Spectrum Policy and Technology

**Spectrum Access and the Promise of Cognitive Radio Technology**

## Spectrum Policy and Cognitive Radios

**Spectrum Policy Task Force recognized the changes in technology and the profound impact that would have to spectrum policy**
- Improved Spectrum Access can mitigate scarcity of the spectrum resource
- Clearly defined interference metrics can improve utilization of the spectrum
- Spectrum can be parceled in frequency, space, and time

**Cognitive radio technology, inclusive of software and software definable radio technology, are key components for realizing this vision**
***Goal is to Promote Efficient Use of the Spectrum!***

## Cognitive and Software and Software-Definable Radio Technology

**Software and Software Definable Radio Capabilities**
- Flexible ... “capable of responding or conforming to changing or new situations”
- Agile ... “marked by ready ability to move with quick easy grace”
**Cognitive Radio Capabilities**
- Cognitive ... “knowing, or apprehending by the understanding”

- Webster’s New Collegiate Dictionary

## Improving Spectrum Efficiency

**Group**
**like systems**

**Permit other****users or uses --**
**flexibility**

**Improve access****through time, ****frequency,****power, bandwidth****and space**

**Throughput Limited**

**Access Limited**

**Adjust regulations****as technology ****develops**

**Discourage****inefficient use**

**Improving Spectrum Efficiency**

## Spectrum Use in Practice

**Some spectrum is intensively used**
**Other spectrum has highly variable use in when viewed in terms of time and geography**

## Spectrum Policy Reform: Access is Key

**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.

## Promoting Access to Spectrum The New Model

**Below the Acceptable **
**“****Interference Temperature”**

**Promoting Access to Spectrum ****The New Model**

- Cognitive Radios

## Promoting Access to SpectrumThrough Increased FlexibilityIllustration: Public Safety & Dynamic Spectrum Use

**CMRS**

**Public Safety**

**Data Services**

**Data Services**

**Public Safety**

**CMRS**

**1%**

**10%**

**100%**

**10%**

**1%**

**Use of public safety spectrum is highly variable**

**Promoting Access to Spectrum****Through Increased Flexibility****Illustration: Public Safety & Dynamic Spectrum Use**

## Interference AvoidanceTolerance of Interference

**Distance from licensed transmitting antenna**

**Power at Receiver**

**Licensed signal**

**Current FCC Power Limits**

**Interference Avoidance****Tolerance of Interference**

**Quantify acceptable levels of interference**
- Can Cognitive Radios capture the Interference Temperature?
- How should Cognitive Radios exploit this information ?

**New Opportunities for Spectrum Access**

**Noise Floor**

**Prevent Aggregation Above Interference Temperature Limit**

**Notes:**
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.

## Promoting Access to SpectrumDiscouraging Inefficient Use

**Situations where the Commission finds it necessary to promote spectrum or technical efficiency**
- Consider user fees or other steps to stimulate improvements in efficiency when marketplace is inadequate.
- To the extent that wireline or hybrid technologies may be more efficient alternatives to existing use of radio spectrum in some instances, promote the use of such alternatives whenever appropriate.

## Key Questions

**Since Cognitive Radios span a large range of capabilities ...**
- What subset of capabilities are needed?
- What subset of capabilities are in hand? Near term? Far term?
**Economics, Reliability, and Capability impact the viability of a technology**
- What are the impediments for a cost-effective system?
- How do we determine the reliability constraints for different applications of Cognitive Radio technology (e.g. public safety, DoD, consumer handsets)

**These Key Questions will hopefully be addressed during this workshop**