July 2010
doc.: IEEE 802.22-10/0121r0
802.22 Coexistence Aspects
Author:
Name
Company
Address
Phone
email
Gerald Chouinard
Communications
Research Centre,
Canada
3701 Carling Ave.
Ottawa, Ontario
Canada K2H 8S2
(613) 998-2500
gerald.chouinard@crc.ca
Abstract
This contribution summarizes graphically the coexistence features developed in the 802.22 Draft Standard.
Notice: This document has been prepared to assist IEEE 802.22. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in
this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE
Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit
others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11.
Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http://standards.ieee.org/guides/bylaws/sb-bylaws.pdf>, including the
statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to
patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the
standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the
Chair Carl R. Stevenson <wk3c@wk3c.com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a
draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>.
Submission
Slide 1
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11
CSMA-CA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 2
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
IEEE Standards
RAN
“Regional Area
Network”
IEEE 802.22
10-30 km
54 - 862 MHz
Submission
Slide 3
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Characteristics of 802.22 WRAN:
Base station power: 100 W
Antenna height: 75 m
16 km
23 km
30 km
64-QAM
16-QAM
QPSK
Max throughput per 6 MHz:
23 Mbit/s (net: 19.44 Mbit/s)
User terminal (CPE) power: 4 W
antenna height: 10 m
Submission
Slide 4
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 5
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.22 WRAN
WRAN CPE
4 Watt
10 m outdoors
WRAN BS
4 Watt
30 m
WRAN edge
of coverage:
10.4 km
Submission
Slide 6
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.22 WRAN
Radius of detection
of BS TX by 802.11=
330 m
at -64 dBm level
WRAN CPE
4 Watt
10 m outdoors
WRAN BS
4 Watt
30 m
WRAN edge
of coverage:
10.4 km
Submission
Slide 7
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.22 WRAN
Radius of detection
of BS TX by 802.11=
330 m
at -64 dBm level
WRAN CPE
4 Watt
10 m outdoors
WRAN BS
4 Watt
30 m
Radius of
Interference from the
100 mW portable
unit= 2.2 km
WRAN edge
of coverage:
10.4 km
Submission
Slide 8
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.22 WRAN
Radius of detection
of BS TX by 802.11=
330 m
at -64 dBm level
On-axis radius of
detection of CPE TX
by 802.11= 300 m
78 m in backlobe
WRAN CPE
4 Watt
10 m outdoors
WRAN BS
4 Watt
30 m
Radius of
Interference from the
100 mW portable
unit= 2.2 km
WRAN edge
of coverage:
10.4 km
Submission
Slide 9
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.22 WRAN
Radius of detection
of BS TX by 802.11=
330 m
at -64 dBm level
WRAN BS
4 Watt
30 m
On-axis radius of
detection of CPE TX
by 802.11= 300 m
78 m in backlobe
WRAN CPE
4 Watt
10 m outdoors
On-axis radius of
Interference from the
100 mW portable
unit= 1.35 km
Radius of
Interference from the
100 mW portable
unit= 2.2 km
WRAN edge
of coverage:
10.4 km
Submission
Slide 10
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 11
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
802.11 Detection threshold level to
coexist with 802.22
• Required 802.11 detection threshold in 6 MHz to limit the
802.22 devices desensitization to 3 dB
–
–
–
–
Detection threshold = -90.8 dBm (BS transmitted signal)
Detection threshold = -88 dBm (CPE transmitted signal)
Detection threshold = -104 dBm (BS signal received at CPE, 10 m)
Detection threshold = -120.9 dBm (BS signal received at CPE, 1.5 m)
• Note that:
To be able to detect the downstream burst
from the distant BS sending the DS/US-MAP
– Typical 802.11 sensitivity = -85 dBm
– Typical SNR (QPSK, rate: 1/2) = 4.3 dB
(Re: 19-07-0011-15-0000-parameters-for-simulation.doc)
– 802.11 desensitization at these thresholds would be:
•
•
•
•
Submission
BS transmited signal = 2.3 dB
CPE transmitted signal = 3.7 dB
BS received signal at CPE (10 m) = 0.14 dB
BS received signal at CPE (1.5 m) = 0 dB
Slide 12
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 13
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Spectrum
etiquette
On-demand
frame
contention
802.22 Coexistence techniques
Coexistence beacon protocol
(Exchange of information between BSs through CPEs
using the self-coexistence window)
Submission
Slide 14
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Spectrum Etiquette
• Co-channel consideration:
– different operating channel for overlapping or adjacent cells
– different first backup channel
6, 4, 2, 5, 7
6, 4, 2, 5
8, 5, 2, 4, 7
8, 5, 2, 4
1
3, 7, 2, 5, 8
1, 2, 7
4, 8, 2, 6, 7
3, 4, 2, 6, 7
3, 2, 5, 8
5, 6, 2, 7, 8
3, 4, 6
7, 5
4, 8, 2, 6
(a)
Submission
2
5, 6, 2, 8
(b)
Slide 15
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Spectrum Etiquette
• Adjacent-channel consideration:
– Depending on adjacent rejection and dynamic range operation
FCC
R&O 08-260
27 27
dBrdBr
IC
RSS-196
55 dBr
55 dBr
802.16 scaled to 6 MHz
802.16 scaled to 6 MHz
Frequency Separation form the Equipment’s Channel Center, Δf (MHz)
Submission
Slide 16
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
On-channel re-use
• Techniques for on-channel re-use
– CDMA: limited signal discrimination (X <25 dB)
– OFDMA: average signal discrimination through FFT (25 < X <35 dB)
– TDMA: very high signal discrimination (X > 35 dB) with
appropriate time buffer to remove channel time spread
Given the potential large dynamic difference between fixed
and portable applications, TDMA will be required.
Submission
Slide 17
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 18
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
160 ms
802.22 WRAN
superframe and
frame structure
...
Superframe n-1
Superframe n
10 ms
10 ms
frame 0
frame 1
Superframe Frame SCH
Preamble Preamble
...
Superframe n+1
Time
10 ms
. . .
Frame
Preamble
frame 15
Frame
Preamble
Ranging/BW request/UCS notification
time buffer
Burst m
Bursts
Burst 2
Bursts
Burst
Burst
Burst
60 subchannels
DS-MAP
more than 7 OFDMA symbols
Burst 3
US-MAP
Frame Preamble
Frame = 10 ms
time buffer
Burst 2
Self-coexistence window (4 or 5 symbols when scheduled)
Burst 1
Burst 1
UCD
DCD
FCH
Superframe = 160 ms
Superframe = 16 frames
US-MAP
26 to 42 symbols corresponding to bandwidths from 6 MHz to 8 MHz and cyclic prefixes from 1/4 to 1/32
Burst n
Submission
Slide 19
RTG
DS sub-frame
TTG
Burst
US sub-frame
(smallest US burst portion on a given subchannel= 7 symbols)
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
160 ms
802.22 WRAN
superframe and
frame structure
...
Superframe n-1
Superframe n
10 ms
10 ms
frame 0
frame 1
Superframe Frame SCH
Preamble Preamble
...
Superframe n+1
Time
10 ms
. . .
Frame
Preamble
frame 15
Frame
Preamble
Ranging/BW request/UCS notification
time buffer
Burst
Burst
Burst
Burst n
Slide 20
RTG
TTG
Burst
DS sub-frame
Submission
Burst m
Bursts
Burst 2
Bursts
60 subchannels
DS-MAP
Frame Preamble
Using the Selfcoexistence window (5
symbols, 2.3 ms) for
TDMA with other
systems
more than 7 OFDMA symbols
Burst 3
US-MAP
Frame = 10 ms
time buffer
Burst 2
Self-coexistence window (4 or 5 symbols when scheduled)
Burst 1
Burst 1
UCD
DCD
FCH
Superframe = 160 ms
Superframe = 16 frames
US-MAP
26 to 42 symbols corresponding to bandwidths from 6 MHz to 8 MHz and cyclic prefixes from 1/4 to 1/32
US sub-frame
(smallest US burst portion on a given subchannel= 7 symbols)
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
160 ms
802.22 WRAN
superframe and
frame structure
...
Superframe n-1
Superframe n
10 ms
10 ms
frame 0
frame 1
Superframe Frame SCH
Preamble Preamble
...
Superframe n+1
Time
10 ms
. . .
Frame
Preamble
frame 15
Frame
Preamble
Ranging/BW request/UCS notification
time buffer
Burst m
Bursts
Burst 2
Bursts
Burst
Burst
Burst
60 subchannels
DS-MAP
Frame Preamble
Using the 802.22
capability to shorten its
frame under lower
traffic
more than 7 OFDMA symbols
Burst 3
US-MAP
Frame = 10 ms
time buffer
Burst 2
Self-coexistence window (4 or 5 symbols when scheduled)
Burst 1
Burst 1
UCD
DCD
FCH
Superframe = 160 ms
Superframe = 16 frames
US-MAP
26 to 42 symbols corresponding to bandwidths from 6 MHz to 8 MHz and cyclic prefixes from 1/4 to 1/32
Burst n
Submission
Slide 21
RTG
DS sub-frame
TTG
Burst
US sub-frame
(smallest US burst portion on a given subchannel= 7 symbols)
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
160 ms
802.22 WRAN
superframe and
frame structure
...
Superframe n-1
Superframe n
10 ms
10 ms
frame 0
frame 1
Superframe Frame SCH
Preamble Preamble
...
Superframe n+1
Time
10 ms
. . .
Frame
Preamble
frame 15
Frame
Preamble
Ranging/BW request/UCS notification
time buffer
Burst m
Bursts
Burst 2
Bursts
Burst
Burst
Burst
60 subchannels
DS-MAP
Frame Preamble
Using the 802.22
capability to schedule
intra-frame quiet
periods for sensing
more than 7 OFDMA symbols
Burst 3
US-MAP
Frame = 10 ms
time buffer
Burst 2
Self-coexistence window (4 or 5 symbols when scheduled)
Burst 1
Burst 1
UCD
DCD
FCH
Superframe = 160 ms
Superframe = 16 frames
US-MAP
26 to 42 symbols corresponding to bandwidths from 6 MHz to 8 MHz and cyclic prefixes from 1/4 to 1/32
Burst n
Submission
Slide 22
RTG
DS sub-frame
TTG
Burst
US sub-frame
(smallest US burst portion on a given subchannel= 7 symbols)
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11
CSMA-CA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 23
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Improving 802.22 operation in presence of
802.11 CSMA-CA transmissions
• 802.11 CSMA-CA based transmission would interfere with
the 802.22 frames where critical information is sent, that is
superframe control header (SCH), frame contol header
(FCH and the DS\US-MAP.
• 802.22 is considering stretching the preamble periods so that
the CSMA-CA burst is completed when this critical
information is sent by the BS.
• Repeating the superframe preamble and frame preambles a
controlled number of times will allow trade-off between
802.22 robustness against CSMA-CA transmissions and
transmission efficiency.
• 802.19 Inter-system coexistence will need to limit the length
of the CSMA-CA bursts to make this approach effective
without excessively affecting the systems throughput.
Submission
Slide 24
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 25
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Terrestrial geolocation
Downstream
BS
Vernier-1
CBP burst
Upstream
Vernier-2
Vernier-1
CPE
2
CPE
1
Vernier-3
•
Besides satellite-based geolocation, the 802.22 standard
includes terrestrial geolocation using inherent capabilities of
the OFDM based modulation and the coexistence beacon
protocol bursts transmitted and received among CPEs
•
Propagation time measured between BS and its CPEs and
among CPEs of the same cell using Fine Time Difference of
Arrival: TDOA
Submission
Slide 26
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Outline
• Summary of 802.22 characteristics
• 802.11 Interference issues
– Detection distance and interference distance
– Detection threshold levels to coexist with 802.22
• 802.22 coexistence tools available to 802.19
– Coexistence techniques in 802.22
• Spectrum etiquette
• On-channel re-use
– Improving 802.22 operation in presence of 802.11 CSMACA transmissions
– Terrestrial geolocation
• Conclusion
Submission
Slide 27
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
Conclusions
• Current 802.11 CSMA-CA based detection thresholds
are not sufficient to enable coexistence with 802.22
• 802.22 WG has been developing a standard based on
protecting incumbents and enabling self-coexistence
since the very beginning
• 802.22 has established spectrum sharing techniques
that can be readily adapted to enable coexistence with
other 802 technologies
• 802.22 spectrum manager is capable of autonomously
deciding which coexistence mechanism to use and how
• 802.22 will consider providing interface between its
spectrum manager and 802.19 coexistence manager
• 802.22 will be happy to help 802.19 to ensure fair
coexistence amongts different 802 technologies in the
TVWS
Submission
Slide 28
Gerald Chouinard, CRC
July 2010
doc.: IEEE 802.22-10/0121r0
References
1.
IEEE P802.22™/ DRAFTv3.0 Draft Standard for Wireless Regional Area
Networks Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and
Physical Layer (PHY) specifications: Policies and procedures for operation in
the TV Bands, April 2010
Submission
Slide 29
Gerald Chouinard, CRC