Tutorial on the P802.22.2 PAR for:“Recommended Practice for the Installation and Deployment of IEEE 802.22 Systems”

Carl R. Stevenson,WK3C Wireless LLCGerald Chouinard,Communications Research Centre, CanadaWinston Caldwell,FOX Broadcasting

Scope of the PARThe document recommends best engineering practices for the installation and deployment of IEEE 802.22 systems to help assure that such systems are correctly installed and deployed.

PurposeTo provide detailed technical guidance to installers, deployers, and operators of IEEE 802.22 compliant systems to help assure that such systems are correctly installed and deployed.

Need for a Recommended Practice

Correct installation and deployment of IEEE 802.22 compliant systems are important to assure that those systems will maximally achieve their design goals in terms of system performance, reliability, and non-interference to incumbent licensed systems with which they will share the TV broadcast bands.

StakeholdersStakeholders are installers, operators, users, and manufacturers of IEEE 802.22 systems.

How it all started!The FCC released a Notice of Proposed Rulemaking, May 25, 2004, proposing to allow unlicensed radio transmitters to operate in the broadcast television spectrum at locations where that spectrum is not being used.

Fixed/AccessTransmitter power limit: 1 WTransmitter antenna gain limit: 6 dBiAn incumbent database is required.Geo-location technique is required using either a GPS or professional installation.Transmission of a unique identifier is necessary.Spectrum sensing approach is postulated.

IEEE 802 Standards Process

IEEE802

802.11WLAN

802.15WPAN

802.16WMAN

802.11g54 Mbit/s

802.11b11 Mbit/s

…

802.15.1Bluetooth

802.15.3High rate

802.11n100 Mbit/s

…

802.16dFixed

802.16eMobile

802.20WMANMobile

802.11jRelay

…

802.15.4Zigbee

Wi-Fi Wi-MAX

802.18Regulatory

Matters

802.18 SG1Use of VHF/

UHF TVbands by LEequipment

IEEE 802 Standards Process

IEEE802

802.11WLAN

802.15WPAN

802.16WMAN

802.11g54 Mbit/s

802.11b11 Mbit/s

…

802.15.1Bluetooth

802.15.3High rate

802.11n100 Mbit/s

…

802.16dFixed

802.16eMobile

…802.20WMANMobile

802.22WRAN

802.22.1Enhanced

Part 74protection

802.22.2Recommended

Practice802.11jRelay

…

802.15.4Zigbee

Wi-Fi Wi-MAX

802.18Regulatory

Matters

IEEE 802.22 Functional Requirements

(primarily related to incumbent protection)1 W transmitter power with a maximum of 4 W EIRP.Fixed point-to-multi-point access only.Base station controls all transmit parameters and characteristics in the network.Base station is professionally installed and maintained.Location awareness for all devices in the networkCustomer Premise Equipment (CPE) antenna is to be installed outdoors at least 10 m above ground.CPE cannot transmit unless it has successfully associated with a base station.Base station uses an up-to-date database augmented by distributed sensing to determine channel availability.

IEEE 802.22

RAN

“Regional Area Network”

IEEE Standards

30-100 km

54 - 862 MHz

Multipath absorption Window

(Cyclic prefix )0.25

2.2 μsec

0.8

33 μsec

18 MbpsBW= 6,7,8 MHz

Reducedrefraction

Dopplerspread

0

10

20

30

40

50

60

70

80

90

100

.03 0.1 1 50.3 3Frequency (GHz)

Rel

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mpl

exity

/cos

t (%

)

Cosmicnoise

Industrialnoise

Ionosphericreflection

Rain fade

Foliageabsorption

%bandwidth

Outdoor/indoorattenuation

Groundwave reach

Filterselectivity

Antennaaperture

Phasenoise

NoiseFigure

Optimum frequency rangefor large area Non-Line-of-sight Broadband Access

Optimum frequency rangefor large area Non-Line-of-sight Broadband Access

0

10

20

30

40

50

60

70

80

90

100

Frequency (GHz)

Rel

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.03 0.1 1 50.3 30.4 0.5 0.6 0.7 0.8 0.9 20.20.15

TVCh. 7-13

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Fixe

d se

c.

TVCh. 14-36

TVCh. 38-69

Met

eoFixe

dM

obile

License-exempt bands

Existing RF spectrum usageMain markets

(Test conducted with antenna at a height of 22.1 metres above the ground in the rural sector west of

Ottawa, Canada)

Broadband IP-based communications below1 GHz Spectrum Occupancy

Low UHF

Rural Broadband: - Cable-modem / ADSL

- WiFi hot-spots in ISM bands- Higher power, lower frequency broadband access system

30 km23 km

20 km

MACLong round-trip

delays

QPSK

16-QAM64-QAM

PHYAdaptive

modulation

CPE Mock-up(RF based on low-cost UHF-TV tuners)

RF Input

RF Output

Ethernet to computer

Power Supply

WRAN System Capacity and Coverage

Typical WRAN service model RF channel bandwidth 6 MHz Typical spectrum efficiency 3 bit/(s*Hz) Channel capacity 18 Mbit/s Per subscriber capacity (forward) 1.5 Mbit/s (peak min.) Per subscriber capacity (return) 384 kbit/s (peak min.) Over-subscription ratio 50:1 Subscribers per forward channel 600

Minimum viable operation Minimum number of subscribers 90 Initial penetration 5 %

Potential full penetration Potential number of subscribers 1,800 Number of person per household 2.5 Population per coverage area 4500

Type of operation USA Other? WRAN base station EIRP limit 4 Watts 100 Watts (?) WRAN user terminal EIRP limit 4 Watts 4 Watts (?) Coverage radius 16.7 km 30.7 km Minimum population density 5.1 person/km2 1.5 person/km2

b

Population density (per km2)

Rel

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exity

/cos

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)

Subu

rban

Urb

an

Den

se u

rban

Rur

al

Spar

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pop

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ed

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10 100 1,000 10,000 100,000

www.crc.cawww.crc.ca

Household reach by technologies (“last mile”)

Optical fiber

Cable modem

ADSLMW wireless

Satellite

802.22 WRAN

0.4 M

0.8 M

1.2 M

1.6 M

2.0 M

0.0 M Popu

latio

n pe

r den

sity

bin

(Mill

ion)

USA (scaled)

Canada

Satellite WRAN100 W Base Station4 W User terminal

ADSL, Cable, ISM and UNII Wireless and Optical Fiber4 W Base Station

FCC Definition of ‘Rural’

Alternate channels interference case

Noise limited contour

41 dB(uV/m)

<= DTV <= WRAN

Saturation of DTV receiver from WRAN transmission => control of transmit power(Co-channel and

1st adj. channel=> keep-out distances)

DTV station

DTV noise-limited contour

135 km

Characteristics of 802.22 WRAN:

30 km23 km

15 km

QPSK

16-QAM64-QAM

Max throughput per 6 MHz:4.2 Mbit/s downstream

384 kbit/s upstream

Max throughput per 6 MHz:23 Mbit/s

Minimum service availability:location= 50%time= 99.9%

Base station power: 4 W (USA)Antenna height: 75 m

User terminal (CPE) power: 4 Wantenna height: 10 m

CPE keep-out distance:Co-channel: 3 km

Adjacent channel: 70 m

BS keep-out distance:Co-channel: 31 km

Adjacent channel: 1 km

Cognitive Radio

Allows spectrum sharing on a negotiated or opportunistic basis.Adapts a radio’s use of spectrum to the real-time conditions of its operating environment.Offers the potential for more flexible, efficient, and comprehensive use of available spectrum.Reduces the risk of harmful interference.

Cognitive Radio Techniques

(as per the NPRM)

1. Database/Geo-Location: Determine whether the unlicensed device is outside the protected contour of a licensed station using a database with a geo-location device.

2. Control Signal: Receive a control signal from an established incumbent service indicating which channels are available or are occupied in the area.

3. Sensing: Sense the RF environment to a certain threshold to detect whether a TV channel is in use.

1- Problems with the Proposed Database/Geo-

Location Technique(as per the NPRM)

Databases can have mistakes and can be inaccurate.Databases are not updated instantaneously with real-time changes in the RF environment.GPS does not operate well indoors (CPE antenna has to be outdoors anyway).Solution: Databases/geolocation techniques could be used for first assessment of channel availability but need to be supplemented by sensing.

2- Problems with the Proposed Control Signal Technique (as per the

NPRM)

Control signals indicating available channels from different sources may overlap and cause confusion.Control signals indicating occupied channels from different sources may overlap and cause confusion.No incentives for incumbent services to provide control signals for unlicensed operation.Solution: control signal provided by the base station

3- Problems with Sensing

(as per the NPRM)

The detectable RF environment changes dramatically with minor changes in location of the sensing device due to multi-path, fading, or shadowing.The “hidden node” problem occurs when a sensing device is being shadowed by either a man-made structure or terrain and cannot accurately detect what TV channels are occupied.Solution: collaborative sensing from a number of CPEs and data fusion/centralized control at the base station, augmented by geolocation/database.

IEEE 802.22 Work PlanSteps Deadline

Formation of the 802.22 WG

Jan 05

Functional Requirements definition & Call for proposals

Sept 05

Proposals / Contributions Nov 05 & Jan 06

Consolidation of proposals March 06Standard drafting process starts

May 06

Sponsor ballot / Comments resolution process March 07Standard approved and delivered to industry January 08

Need for Recommended Practice

Recommended Practice is needed to help operators make best use of the spectrum while protecting incumbentsInstallation and deployment requirements to protect incumbents need to be well understoodTypical WRAN deployment and installation need to be explained to new potential operatorsCapabilities and limitations of the 802.22 standard need to be knownImpact of departure from typical operation needs to be understood

What theRecommended Practice

may cover:

Best practices for base station siting and installation:

Site selection and frequency selection based on local TV channel usageUse of computer based coverage prediction tools and databases to identify potential coverage area and potentially affected incumbentsTransmit antenna and power constraints for given locationCo-existence with neighbour WRAN operators

Best practices for Base Station operation and performance verification:

Continuous monitoring of the interference environment

Normal sensing reporting Special sensing request to CPEs and reporting Data fusion and automatic and/or manual frequency

channel controlInterface with the incumbents for interference resolutionSmooth increase of service provision by using multiple channels

Load balancing Fall-back scheme in case of interference and

insufficient channelsMonitoring of key operational and performance parameters

Best practices for CPE installation and control:

Verification of physical location (at registration, GPS, relative position among CPEs)Verification of the installation (10 m high antenna, right azimuth, fixed installation: remote, visual)Instruction to new subscribers (installation and antenna alignment, problem identification, network access)Guidance on serving subscribers near the edge of the coverage versus system loading and interference potential

Best practices for interference avoidance:

Optimizing collaborative sensing based on a number of well positioned CPEs relative to an incumbent operationTechniques for improved coexistence among WRAN operators in the same area

Best practices for Part 74 device protection

How to maximize the sensing capability of BS and CPEs for wireless microphones and the limitationsUse of enhanced detection schemes (TG1)Means for the operator to avoid interference Channel switch in the local vicinity based on

location information

Conclusions802.22 sees a compelling need to develop such a Recommended PracticeThe PAR was everwhelmingly approved by the 802.22 WG membersLicensed incumbents wholeheartedly support the development of this Recommended Practice802.22 wants to proceed and will be seeking EC approval to submit the PAR to NesCom