Spectrum Agile Radio

1. Spectrum Agile Radio Team 4 Jim Kile Don Little Samir Shah

2. Structure of Presentation • Definition, why?, and evolution • Background concepts • White space, measurements • Regulatory environment • Wireless standards • Implementations

3. Spectrum Agile Radio (SAR) Use of a licensed radio band by other than the license holders on a non-interfering basis.

4. WHY? • Wireless LAN’s & MAN’s • Palm • PocketPC • Blackberry • Cell phone • Wearable computing • Other consumer electronics

5. Evolution of Devices Necessary radio spectrum will not be available in the future

6. HOW? • Almost all radio bands suitable for wireless communications have been allocated • Preliminary studies indicate that much of the radio spectrum is not in use • For a significant amount of time • At large numbers of locations

7. Definition Radio resources • Radio frequency bands • Can be used/occupied • For certain duration • In a certain area • Called “footprint”

8. DefinitionPrimary Users • Conventional legacy users • Rightful owners • Hardware and protocols have strict priority on spectrum access • Should not be required to retrofit to meet secondary user access needs

9. DefinitionSecondary users • Spectrum-agile devices • Sense environment • Adapt to appropriate • Frequency • Power • Transmission schemes • Opportunistically access unused spectrum vacated by idle primaries

10. DefinitionRules for Coexistence • When a primary user is using the band • Secondary users are not allowed to co-exist • Channel availability of secondary users determined by the activities and properties of primary users

11. DefinitionOpportunistic Spectrum Utilization • Usage by Secondary Users • On a non-interfering basis • Band not used • Used in deterministic pattern • CURRENTLY ILLEGAL

12. DefinitionSpectrum Agile Radio • Communicates using available radio resources • Licensed to OTHER radio services • Without interfering with the operation of licensed radio devices

13. Spectrum Agile Radio

14. Definition: White Space • Almost all of the radio spectrum has been allocated • But, there are areas of the radio spectrum not currently in use by primary user • A band is counted as white space when: • Wider than 1 MHz and • Remains unoccupied for 10 minutes or longer • Significance? • Resource is scarce • Provides an opportunity for dynamic spectrum usage

15. White Space Example

16. White Space Example – Even in the unlicensed spectrum Return

17. Measuring Spectrum White Space • Why? • Understand the amount of under-utilized spectrum • Conditions • 30 MHz to 3,000 MHz (3 GHz) • Use a “worse case” location • Downtown Washington, DC • Both government and commercial spectrum use • Several hour duration during high use periods

18. Spectrum Measurement Requirements • Elevated location • Higher detection probability • Eliminates line of site obstacles • Use of high quality RF equipment • Detection sensitivity

19. Whitespace Estimate • Study conducted in June 2003 by the Shared Spectrum Company • What constitutes white space for this estimate? • Bands ³ 1MHz wide • Unoccupied for 10 minutes or longer • 62% white space in the licensed spectrum

20. Regulatory Environment • Bandwidth is a natural resource • Heavily regulated • Expensive • A 3 GHz mobile communications band costs $17 Billion! • In the U. S., almost all bandwidth is allocated (licensed)

21. Regulatory Environment- U. S. FCC Models • Licensed primary user model • Set aside for exclusive use • Examples: TV and radio • Unlicensed non-exclusive use model • Set aside for non-exclusive use • Examples: ISM band applications such as Wireless LAN (802.11) or Bluetooth • Represents a small fraction of the total bandwidth available

22. Regulatory Environment circa 1940 • “Dumb device” assumption • Tightly regulated to prevent interference • Example: Television VHF/UHF band channel allocation • No way to share inefficiently used spectrum

23. Regulatory Environment Today • Fast processing power and intelligent radios • New technology which is more tolerant to interference • Spread spectrum • Spectrum agile radio

24. Regulatory Environment Today • Introducing underlays/noisefloor rights • Developing a noise temperature measure • Devices measure the level of interference and transmit according • Development of co-existencemodes • Allow multiple uses of aspectrum (spectrum agileradio – SAR)

25. Regulatory EnvironmentSpectrum policy task force • Setup by Chairman Michael Powell in June 2002 • Headed by Paul Kolozdy • Purpose • Conduct a comprehensive review of spectrum policy • Modernize spectrum management and utilization rules • “Command and control”  consumer-oriented • Submitted findings and recommendations in December 2002

26. Regulatory EnvironmentSpectrum Policy Task Force “[T]he time is ripe for spectrum policy reform. Increasing demand for spectrum-based services and devices are straining longstanding, and outmoded, spectrum policies. While the Commission has recently made some major strides in how spectrum is allocated and assigned in some bands . . . spectrum policy is not keeping pace with the relentless spectrum demands of the market.”

27. Findings Spectrum access versus scarcity New methods as a solution to access Interference tolerance Need to define rights and responsibility Recommendations Modernizing the regulator model Increase access to spectrum through the time dimension New inferences management standards Legislative recommendations Regulatory EnvironmentSpectrum policy task force

28. Regulatory EnvironmentFCC 2005 Rule Changes • March 2005, FCC adopts rule changes for smart radios • Allows sharing spectrum with primary users without causing harmful interference • Regulate emission characteristics rather than the type of service • Allows rapid development of new applications • Unencumbered by regulatory delays

29. Regulatory EnvironmentFCC 2005 Rule Change Principles • Provide reasonable security measures to prevent unauthorized software modifications affect the RF operating parameters • Manufacturer to supply a high level operational description of the software that controls the radio’s RF characteristics • A description of the software security measures employed to prevent unauthorized modifications

30. Regulatory EnvironmentFCC 2005 Rule Change Principles cont’d • Manufacturers to market radios that have the hardware-based capability to transmit outside authorized United States frequency bands • Required software controls to limit operation to authorized frequency bands when used in the United States.

31. Regulatory Environment FCC 2005 • Commission concluded that • Technical measures that cognitive radios can employ will allow a reliable secondary use of licensed spectrum • Maintains • Availability of the spectrum • Rapid reversion to the licensee when needed • Saw no need to adopt any particular technical model for interruptible spectrum leasing

32. Defense Advanced Research Projects Agency (DARPA) • Working on developing new technologies • Allow multiple radio systems to share the spectrum through adaptive mechanisms • NeXt Generation communications (XG) program • Identify behaviors versus detailed descriptions • Dynamically align rules with technologies for future radio systems

33. DARPA • NeXt Generation communications (XG) program concepts (continued) • Abstract behaviors, protocols, and a policy language • Flexibility, long-term impact, and the need for regulatory approval

34. US Army • “Adaptive Spectrum Exploitation” (ASE) • Real-time spectrum management in the battlefield • “Tactical battlefield spectrum management” • Importance of spectrum planning • Dynamic apportionment • Dynamic interference resolution

35. Spectrum Agile RadioSalient Features • Rules for radios as opposed to rules for services/applications • Radio regulators will continue to decide policy that specify behaviors of these radios • Spectrum sharing, interference management, and coordination between users, based on radio environment awareness • Real-time measurements, dissemination and opportunity identification

36. Spectrum Agile RadioSalient Features • Awareness of primary and secondary usage • Radio behaviors influenced by evolving policies • Policies set by regulators • Policies for wireless network management • Examples: • For U-NII bands, using etiquette as discussed in Wi-Fi • For hospitals

37. IEEELAN/MAN Standards Series • Local Area Network standards • Metropolitan Area Network standards • Task Groups (TGs) to develop extensions • IEEE 1900 Next Generation Radio Standards • IEEE 802.22 Wireless Regional Area Networks • IEEE 802.11 Wireless Local Area Networks • 802.11h Spectrum Managed 802.11a • 802.11k Physical measurement of wireless energy

38. IEEE 1900 Next Generation Radio Standards • Established in the first quarter 2005 • IEEE Communications Society (ComSoc) • IEEE Electromagnetic Compatibility (EMC) Society • Develop supporting standards • Next generation radio • Advanced spectrum management

39. IEEE 802.22 Wireless Regional Area Networks • Working Group on Wireless Regional Area Networks • Develop standard for spectrum agile radio-based air interface • License-exempt devices on a non-interfering basis • Spectrum allocated to TV Broadcast Service

40. IEEE 802.11 Wireless Local Area Networks • Current wireless LAN standard • 802.11h Spectrum Managed 802.11a • 802.11k Physical measurement wireless energy

41. IEEE 802.11h Spectrum Managed 802.11a • Resolve interference issues 802.11a in 5 GHz band • Military radar systems • Medical devices • Satellite communications • Transmit Power Control (TPC) • Dynamic Frequency Selection (DFS)

42. IEEE 802.11h Dynamic Frequency Selection (DFS) • Detects the presence/type of other devices on a channel • Requires quiet periods • Responds based upon type of device identified • When radar is identified • Devices MUST change channels • Will coexist with other 802.11 traffic

43. IEEE 802.11k “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Radio Resource Management of Wireless LANs” • Final approval of this amendment is targeted for January 2007 • Defines measurement framework

44. IEEE 802.11kWhere? • IEEE 802.11 wireless local area networks operate in the unlicensed • 2.4 GHz Industrial, Scientific and Medical (ISM ) • 4.9 GHz (Japan) • 5 GHz Unlicensed National Information Infrastructure (UNII) bands

45. IEEE 802.11kWhy? • Enable more accurate and efficient operation of Wireless LANs • Optimize radio environments • More devices can coexist • Reduce wireless network traffic congestion

46. IEEE 802.11kHow? • Enhanced measurements and diagnostics • Medium sensing measurement requests and reports • Collects spectrum usage patterns

47. IEEE 802.11kWhat? • Provides information about other radio systems on a channel • Could be 802.11 devices • Could be non-802.11 radiators such as a microwave • Can derive operational parameters for 802.11 stations

48. IEEE 802.11kStandards • Radio resource measurements not standardized • Standardized frame formats • Request for a specific measurement • One radio device to another • Report of such a measurement • Response to the request

49. IEEE 802.11k What do you want to know? • Is channel suitable for use? • Percent busy • Non-802.11 signals • Patterns of these Non-802.11 signals

50. IEEE 802.11k Clear Channel Assessment (CCA) • Logical function found within physical layers • Determines the current state of use of wireless medium • Aids in contention avoidance • Process that determines if the device can transmit on the channel