Wireless TutorialPart 4

White Spaces and Beyond

Brough TurnerDialogic

Fanny MlinarskyoctoScope

Agenda10:30 – 12:00 noon Our G-enealogy – History and Evolution of

Mobile Radio Lunch

1:00 – 2:00 The IEEE’s Wireless Ethernet Keeps Going and GrowingBreak

2:00 – 2:45 4G Tutorial: Vive la Différence?3:00 – 3:45 Mobile Broadband - New Applications and

New Business ModelsBreak

4:00 – 4:45 Tutorial: White Spaces and Beyond

Radio Spectrum Occupancy

As measured by Shared Spectrum Company and the University of Kansas Center for Research for the

NSF National Radio Network Research Testbed (NRNRT)

Urban areas, 30 MHz to 3 GHz. Above 3 GHz mostly vacant.

New York CityUnusually heavy communications during Republican National ConventionAugust 30 to September 3, 2004 brought spectrum occupancy up to 13%.

Most spectrum idle most of the time

• FCC Regs protect obsolete technology– e.g. TV guard bands are to protect pre-1950

receiver technology. You wouldn’t run your business on a 1950s mainframe computer…

• Rights holders utilizing subset of their rights– Governmental entities sitting on spectrum– Partial buildouts; financial or tech problems;

market changes; incumbents sitting on spectrum.

Spectrum Myths

• Spectrum is scarce

• 4G is the future of wireless

• Auctions drive efficient use of spectrum

• Utilization requires massive investments

History of spectrum regulation

• Early radio receivers very primitive– Only understood separation by frequency– Difficulty separating the desired signal

meant large guard bands were required

• Conclusion: spectrum = scarce resource– Radio Act of 1927 creates FRC– Communications Act of 1934 creates FCC

Visible light analogy• Visible light, a (small) part of the spectrum

• Human vision, a really excellent receiver– Eyes plus our (cognitive) visual cortex– Works despite (because of) broadband noise

sources like the sun, the lights in this room– Extremely directional, motion sensitive, …

• Better receivers better spectrum use– Enormous improvements possible

Spectrum Abundance

• Original thinking was wrong– More transmitters, alternate paths, motion –

all serve to increase capacity• More data receiver has about environment the

better it can do at extracting the desired signal

• MIMO and beamforming key to 4G– And beyond. Orders of magnitude to go.

• 4G will be followed by 5G, 6G and so on!– New RF and new networking, e.g. meshes

The Ultimate Metric: bps per Hertz per acre per watt

1

2

3

4

5

6

7

1

2

3

4

5

6

7

572

2

11

2

3

4

5

6

7

3

30–50 mi.

Other myths

• Auctions drive efficient use of spectrum– And yet there has been more innovation in

WiFi than in all of 2G, 3G, 4G cellular bands– OFDM, MIMO – WiFi leads, cellular follows

• Utilization requires massive investments– E.g. spectrum purchase; network buildout– But in license-exempt bands access is free

and radios are purchased by individuals

Spectrum policy

• Today all spectrum is regulated (by the FCC or NTIA), but– Regulation limits technology deployment– Regulation or policy change takes years– Incumbents play policy game very well– Startups have limited runways– Investors don’t like regulatory uncertainty– FCC in the business of regulating “speech”

Spectrum vs. printing presses• Supreme Court lenient on regulation of spectrum

because spectrum is “unusually scarce”

• Prof. Stuart Minor Benjamin, Duke University– The Court has never confronted an allegation that

government actions resulted in unused or underused spectrum, ... Government limits on the number of printing presses almost assuredly would be subject to heightened scrutiny and would not survive such scrutiny.

Prospects for Change• Substantial vested interests

– Broadcasters, cellular operators, many other existing spectrum owners

• Overwhelming success of WiFi, Bluetooth– Commercial successes new interests

• Intel, Google, Microsoft, Apple

• Rural wireless ISPs– Frequently leverage unlicensed technology– Get attention in Congress

Gaining access to spectrum• “License-exempt” began in “junk” bands

– ISM (900 MHz, 2.4 GHz)– Extended into UNII (5 GHz) and 60 GHz

• Underlays – Low power (below licensees)– “Ultra Wideband” in 3.1–10.6 GHz

• Shared use with “lite-licensing”– 3650-3700 MHz ; license-exempt based on

listen-before-talk, location & licensed beacon– Managed by 802.11y protocols from IEEE

Secondary Use• TV White Spaces

– Multi-year battle vs. strong vested interests– Favorable FCC decision – Nov. 2008– Tight restrictions likely to be eased over time, based

on new technology and actual field experience

• Prospect for additional bands?– More access at 5 GHz? potentially under 802.11y– IMT-Advanced candidate bands (2300-2400, 2700-

2900, 3400-4200, and 4400-5000 MHz) will take years to clear but could be used now under 802.11y

TV Spectrum Availability• 6 MHz TV channels 2-69

– VHF: 54-72, 76-88, 174-216 MHz

– UHF: 470-806 MHz

• 2009 transition from analog to digital TV frees up channels 52-69 due to higher spectral efficiency of digital TV

• FCC is updating its regulations and has recently allowed the use of cognitive radio for White Spaces, unused TV spectrum

• WSD = white spaces device

White Space Channel Availability

Approximate White Space UHF channel availability based on full-service post-transition broadcast station allocation

Available Channels: 1 or none 3 or fewer10 or fewer20 or more30 or more

duTreil, Lundin & Rackley, Inc. Sarasota, Florida

White Spaces Radio Technology

• The new regulations (FCC Dockets 04-186, 02-380) require the use of cognitive radios to determine whether a channel is available prior to transmitting.

• Two types of services are targeting TV spectrum:

– Fixed services: WRAN (wireless rural area networks), being standardized by IEEE802.22

– Mobile services: White Spaces, being advocated by the WIA (www.wirelessinnovationalliance.org)

– IEEE 802 LAN/MAN committee formed new study group in November, 2008 to investigate white spaces standardization

Detecting Licensed Transmissions

• Methods for detecting licensed transmissions:– An internal GPS could be used in conjunction with a

database to determine whether the WSD is located far enough away from licensed stations.

– WSD could receive information from a broadcast station indicating which channels are available.

– WSD could incorporate sensing capabilities to detect whether licensed transmitters are in its range. If no signals are detected, the device could transmit. If signals are detected, the device would have to search for another channel.

• FCC sensing thresholds : – -116 dBm for ATSC (Advanced Television Systems

Committee, digital TV)

– -94 dBm for NTSC (National Television System Committee, analog TV)

– -107 dBm for wireless microphones

Protected devices: TV stations, wireless microphones

Hidden Node Scenario

TV signal attenuated by an obstruction (wall) is undetectable by a WSD. WSD transmits, interfering with TV broadcast, which is received unobstructed by a rooftop antenna.

TV broadcast received by an

unobstructed rooftop TV antenna

Beach-front Property?• Lower frequencies experience lower

attenuation in free space and through obstructions, e.g. buildings

• However, when propagating through metal frames in modern buildings, Fresnel zone gets constricted and attenuation is introduced

• Antenna size also matters – optimum length is a multiple of ¼ wavelength

– 3.3 feet for 70 MHz– 4” for 700 MHz– 1” for 2.4 GHz

• Longer antennas required for UHF may be problematic for handheld devices

Antenna Fresnel Zone

• Fresnel zone is the shape of electromagnetic signal and is a function of frequency

• Constricting the Fresnel zone introduces attenuation and signal distortion

r = radius in feetD = distance in milesf = frequency in GHz

D

Example: D = 0.5 miler = 30 feet for 700 MHzr = 16 feet for 2.4 GHzr = 10 feet for 5.8 GHz

r

Hidden Node – an Issue?• Analysis and field testing done by ITU-R, FCC

and other organizations demonstrate that even when a WSD is deep inside a building, the signal reaching it is likely to be at most 30 dB lower than the signal at a rooftop antenna.

• The 802.22 draft sets the detection threshold 30 dB below a tuner’s lowest receive level and states that an unlicensed device must detect a broadcast within 2 seconds and with probability of >=90%.

Turf Battles to Continue…• Broadcasters and

traditional wireless operators will continue to oppose TV White Spaces developments

• The battle lines are drawn and the stakes are high

www.octoscope.com

Brough Turner, Chief Strategy Officer, Dialogicbrough.turner@dialogic.com

Blog: http://blogs.nmss.com/communications/

broughturner@gmail.com Skype: brough

AdditionalReferenceMaterial

Mobile Standard Organizations

ARIB(Japan)

T1(USA)

ETSI(Europe)

TTA(Korea)

CWTS(China)

TTC(Japan)

TIA(USA)

Third GenerationPatnership Project

(3GPP)

Third GenerationPartnership Project II

(3GPP2)

ITU

MobileOperators

ITU Members

IS-95), IS-41, IS-2000, IS-835

GSM, W-CDMA,UMTS

Partnership Projects and Forums • ITU IMT-2000: http://www.itu.int/home/imt.html • Mobile Partnership Projects

– 3GPP : http://www.3gpp.org

– 3GPP2 : http://www.3gpp2.org

• Mobile marketing alliances and forums– GSM Association: http://www.gsmworld.com/index.shtml

– UMTS Forum : http://www.umts-forum.org

– CDMA Development Group: http://www.cdg.org/index.asp

– Next Generation Mobile Networks Alliance: http://www.ngmn.org/

– Global Mobile Suppliers Association: http://www.gsacom.com

– CTIA: http://www.ctia.org/

– 3G Americas: http://www.uwcc.org

Mobile Standards Organizations• European Technical Standard Institute (Europe):

– http://www.etsi.org

• Telecommunication Industry Association (USA):– http://www.tiaonline.org

• Alliance for Telecommunications Industry Solutions (USA)(formerly Committee T1):

– http://www.t1.org & http://www.atis.org/

• China Communications Standards Association (China):– http://www.cwts.org

• The Association of Radio Industries and Businesses (Japan):– http://www.arib.or.jp/english/index.html

• The Telecommunication Technology Committee (Japan):– http://www.ttc.or.jp/e/index.html

• The Telecommunication Technology Association (Korea):– http://www.tta.or.kr/english/e_index.htm

Other Industry Consortia• OMA, Open Mobile Alliance:

http://www.openmobilealliance.org/– Consolidates Open Mobile Architecture, WAP Forum, Location

Interoperability Forum, SyncML, MMS Interoperability Group, Wireless Village

• Lists of wireless organizations compiled by others:– http://www.wipconnector.com/resources.php – http://focus.ti.com/general/docs/wtbu/wtbugencontent.tsp?templ

ateId=6123&contentId=4602

– http://www.wlana.org/pdf/wlan_standards_orgs.pdf

Wireless MAN, LAN and PAN Links• WirelessMAN – Broadband Access (WiMAX)

– IEEE 802.16: http://www.ieee802.org/16/ – WiMAX Forum: http://www.wimaxforum.org/home/

• Wireless LAN (WiFi)– IEEE 802.11: http://www.ieee802.org/11/ – WiFi Alliance: http://www.wi-fi.org/ – Wireless LAN Association: http://www.wlana.org/

• Wireless WPAN (Bluetooth)– IEEE 802.15: http://www.ieee802.org/15/ – Bluetooth SIG: https://www.bluetooth.org/

and http://www.bluetooth.com/

Market & Subscriber StatisticsFree:• http://en.wikipedia.org/wiki/List_of_mobile_network_operators

– http://en.wikipedia.org/wiki/List_of_mobile_network_operators_of_Europe

– http://en.wikipedia.org/wiki/List_of_mobile_network_operators_of_the_Americas

– http://en.wikipedia.org/wiki/List_of_mobile_network_operators_of_the_Asia_Pacific_region

– http://en.wikipedia.org/wiki/List_of_mobile_network_operators_of_the_Middle_East_and_Africa

• http://www.gsmworld.com/roaming/gsminfo/index.shtml • http://www.cdg.org/worldwide/cdma_world_subscriber.asp • http://www.gsacom.com/news/statistics.php4

Nominal cost:• http://www.itu.int/ITU-D/ict/publications/world/world.html

www.octoscope.com

Brough Turner, Chief Strategy Officer, Dialogicbrough.turner@dialogic.com

Blog: http://blogs.nmss.com/communications/

broughturner@gmail.com Skype: brough