tutorial on the p802.22.2 par for: recommended practice for the installation and deployment of ieee...
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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 LLC
Gerald Chouinard,Communications Research Centre, Canada
Winston Caldwell,FOX Broadcasting
Scope of the PAR
The 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.
Purpose
To 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.
Stakeholders
Stakeholders 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/Access
Transmitter 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 )
0.252.2 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
ativ
e co
mp
lexi
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ost
(%
)
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
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80
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100
Frequency (GHz)
Rel
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ost
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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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TVCh. 14-36
TVCh. 38-69
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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
ativ
e co
mp
lexi
ty/c
ost
(%
)
Su
bu
rba
n
Urb
an
De
ns
e u
rba
n
Ru
ral
Sp
ars
ely
po
pu
late
d
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 Po
pu
lati
on
pe
r d
en
sit
y b
in (
Mil
lio
n)
USA
(scaled)
Canada
Satellite WRAN100 W Base Station4 W User terminal
ADSL, Cable, ISM and UNII Wireless and Optical Fiber
4 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 Plan
Steps DeadlineFormation 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 06
Standard drafting process starts
May 06
Sponsor ballot / Comments resolution process March 07
Standard 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 control
Interface 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 channels
Monitoring 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 operation
Techniques 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
Conclusions
802.22 sees a compelling need to develop such a Recommended Practice
The PAR was everwhelmingly approved by the 802.22 WG members
Licensed incumbents wholeheartedly support the development of this Recommended Practice
802.22 wants to proceed and will be seeking EC approval to submit the PAR to NesCom