doc.: ieee 802.22-06/0005r5 submission march 2006 etri, ft, i2r, motorola, philips, samsung,...
TRANSCRIPT
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 1
doc.: IEEE 802.22-06/0005r5
Submission
A PHY/MAC Proposal for IEEE 802.22 WRAN Systems
IEEE P802.22 Wireless RANs Date: 2006-03-08Authors:
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 802.22.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 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 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at [email protected].>
Name Company Address Phone Email
John Benko France Telecom (FT) USA [email protected]
Yoon Chae Cheong SAIT Korea +82-31-280-9501 [email protected]
Carlos Cordeiro Philips USA +1-914-945-6091 [email protected]
Wen Gao Thomson Inc. USA +1-609-987-7308 [email protected]
Chang-Joo Kim ETRI Korea +82-42-860-1230 [email protected]
Hak-Sun Kim Samsung Electro-mechanics Korea +82-31-210-3500 [email protected]
Stephen Kuffner Motorola USA +1-847-538-4158 [email protected]
Joy Laskar Georgia Institute of Technology USA +1-404-894-5268 [email protected]
Ying-Chang Liang Institute for Infocomm Research Singapore +65-68748225 [email protected]
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 2
doc.: IEEE 802.22-06/0005r5
Submission
Co-AuthorsName Company Address Phone email
Myung-Sun Song ETRI Korea +82-42-860-5046 [email protected]
Soon-Ik Jeon ETRI Korea +82-42-860-5947 [email protected]
Gwang-Zeen Ko ETRI Korea +82-42-860-4862 [email protected]
Sung-Hyun Hwang ETRI Korea +82-42-860-1133 [email protected]
Bub-Joo Kang ETRI Korea +82-42-860-5446 [email protected]
Chung Gu Kang ETRI Korea +82-2-3290-3236 [email protected]
KyungHi Chang ETRI Korea +82-32-860-8422 [email protected]
Yun Hee Kim ETRI Korea +82-31-201-3793 [email protected]
Moon Ho Lee ETRI Korea +82-63-270-2463 [email protected]
HyungRae Park ETRI Korea +82-2-300-0143 [email protected]
Martial Bellec France Telecom France +33 2 99 12 48 06 [email protected]
Denis Callonnec France Telecom France +33-4-76-764412 [email protected]
Luis Escobar France Telecom France +33-2-45-294622 [email protected]
Francois Marx France Telecom France +33-4-76-764109 [email protected]
Patrick Pirat France Telecom France +33-2-99-124806 [email protected]
Kyutae LimGeorgia Institute of
TechnologyUSA +1-404-385-6008 ktlim @ece.gatech.edu
Youngsik HurGeorgia Institute of
TechnologyUSA +1-404-385-6008 yshur @ece.gatech.edu
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 3
doc.: IEEE 802.22-06/0005r5
Submission
Co-AuthorsName Company Address Phone Email
Wing Seng Leon I2R Singapore +65-68748225 [email protected]
Yonghong Zeng I2R Singapore +65-68748225 [email protected]
Changlong Xu I2R Singapore +65-68748225 [email protected]
Ashok Kumar Marath I2R Singapore +65-68748225 [email protected]
Anh Tuan Hoang I2R Singapore +65-68748225 [email protected]
Francois Chin I2R Singapore +65-68748225 [email protected]
Zhongding Lei I2R Singapore +65-68748225 [email protected]
Peng-Yong Kong I2R Singapore +65-68748225 [email protected]
Chee Wei Ang I2R Singapore +65-68748225 [email protected]
Yufei Blankenship Motorola USA +1-847-576-1902 [email protected]
Brian Classon Motorola USA +1-847-576-5675 [email protected]
Fred Vook Motorola USA +1-847-576-7939 [email protected]
Jeff Zhuang Motorola USA +1-847-538-5924 [email protected]
Kevin Baum Motorola USA +1-847-576-1619 [email protected]
Tim Thomas Motorola USA +1-847-538-2586 [email protected]
David Grandblaise Motorola France +33 1 69 35 25 82 [email protected]
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 4
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Submission
Co-AuthorsName Company Address Phone email
Dagnachew Birru Philips USA +1-914-945-6401 [email protected]
Kiran Challapali Philips USA +1-914-945-6357 [email protected]
Vasanth Gaddam Philips USA +1-914-945-6424 [email protected]
Monisha Ghosh Philips USA +1-914-945-6415 [email protected]
Gene Turkenich Philips USA +1-914-945-6370 [email protected]
Duckdong Hwang SAIT Korea +82 31 280 9513 [email protected]
Chung Jaehak SAIT Korea +82-32-860-8421 [email protected]
Kim Jaemyeong SAIT Korea +82-32-860-8420 [email protected]
Ashish Pandharipande SAIT Korea +82 010-6335-7784 [email protected]
Yoo Sangjo SAIT Korea +82-32-860-8304 [email protected]
Jeong Suk LeeSamsung Electro-
MechanicsKorea +82-31-210-3217 [email protected]
Chang Ho LeeSamsung Electro-
MechanicsKorea +82-31-210-3217 [email protected]
Wangmyong WooSamsung Electro-
MechanicsKorea +82-31-210-3217 [email protected]
David MazzareseSamsung Electronics Co.
Ltd.Korea +82 10 3279 5210
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 5
doc.: IEEE 802.22-06/0005r5
Submission
Name Company Address Phone email
Baowei JiSamsung Telecom
AmericaUSA +1-972-761-7167 [email protected]
Max Muterspaugh Thomson Inc. USA +1-317-587-3711 [email protected]
Hang Liu Thomson Inc. USA +1-609-987-7335 [email protected]
Paul Knutson Thomson Inc. USA +1-609-987-7314 [email protected]
Josh Koslov Thomson Inc. USA +1-609-987-7337 [email protected]
Co-Authors
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 6
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Submission
Presentation Outline
• PHY Proposal
• Updates to the MAC Proposal
• Conclusions
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 7
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Submission
Presentation Outline
• PHY Proposal
• Updates to the MAC Proposal
• Conclusions
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 8
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Submission
Disclaimer
• The following set of slides represent the joint ETRI-France Telecom-I2R-Motorola-Philips-Samsung-Thomson PHY proposal
• This is in contrast to the MAC presentation, which is confined to describe only the updates
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 9
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Submission
PHY Outline• Overview/ Channel bonding
• Fractional Bandwidth
• Sub-Channelization, pilot insertion
• Error Correction Coding
• Multiple antenna
• Sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 10
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Submission
PHY Overview
• OFDMA both in uplink and downlink• QPSK, 16-QAM, and 64-QAM, transformed-QPSK • More than 30 sub channels per TV channel• Contiguous channel bonding upto 3 TV channels (and
beyond in a stack manner)• Data rate range from 5Mbps to 70Mbps• TDD, FDD
RandomizerModulation(constellationmapping)
InterleaverFEC
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 11
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Submission
What We Have Proposed ….
• Adaptively scalable to spectrum availability• Channel Bonding • New frame structure for CR-enabled operation• Enhanced PHY features - Adaptive sub-carrier allocation - Adaptive pilot insertion - Enhanced channel coding (LDPC, Turbo Code,
SBTC) - Multiple antenna options
Known and proven technology
for broadband fixed/mobile wireless access
(e.g., IEEE 802.16d/e – WiBro in Korea)
AdaptiveOFDMA
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 12
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Submission
Advantages of Adaptive OFDMA Proposal
• Flexible Bandwidth Allocation– To use the partial bandwidth (1, 2, 3, 4, 5, 6, 7, 8 MHz) adaptively,
depending on the channel state information (availability)
– To fully utilize available bandwidth under a unified PHY framework
• Single Sampling Frequency– Sampling frequency is the same for all FFT modes.
• Constant Subcarrier Spacing– The subcarrier spacing is constant for all different channel
bandwidths Robust to the frequency offset
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 13
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Submission
PHY (Baseband) Architecture
RandomizerEncoderPuncturer
&Interleaver
MapperSubcarrierAllocator
S/ P
Preamble&
PilotInsertion
IFFTGuard
InsertionP/ S
AWGN
Channel
De-randomizer
Decoder
De-interleaver
&Depuncturer
De-mapper
SubcarrierDeallocator
P/ SChannel
EstimationFFT
GuardRemoval
S/ P
Synchronization
BinaryData
RecoveredData
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 14
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Submission
System Parameters: ProposedParameters Specification Remark
Frequency range 54~862 MHz
Service coverage Typical range 33 km,
Bandwidth• Mandatory: 6, 7, 8 MHz with channel bonding• Optional: fraction BW
Allows the fractional use of TV channel and channel bonding up to 3 TV channels
Data rate• Maximum: 70 Mbps• Minimum: 4.5 Mbps
Maximum of 23 Mbps for 6 MHz
Spectral Efficiency• Maximum: 3.94 bits/s/Hz• Minimum: 0.75 bits/s/Hz
Single TV channel BW of 6 MHz
Modulation QPSK, 16QAM, 64QAM
Transmit power Default 4W EIRP
Multiple Access Adaptive OFDMA Partial bandwidth allocation
FFT Mode 1024, 2048, 4096, 6144
Cyclic Prefix Mode 1/4, 1/8, 1/16, 1/32
Duplex TDD or FDD
Network topology Point-to-Multipoint Network
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 15
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Submission
Channel Bonding: Motivation
• Spectrum occupancy measurements conducted by Shared Spectrum Company from January/2004 to August/2005 have shown that:
• “There is a significant amount of spectrum available in continuous blocks that are 1 MHz and wider ”
• “A dynamic spectrum sharing radio with a low agility, contiguous waveform will provide high utility”
• The November 18, 2005, study from Freepress and New America Foundation (entitled “Measuring the TV “White Space” Available for Unlicensed Use”) reveals that there exists a considerable amount of contiguous vacant TV channels (especially in the upper UHF band)
• More can be expected in other countries
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 16
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Submission
Contiguous open spectrum available!
Example: Jackson, Mississippi
Source: “Measuring the TV ‘White Space’ Available for Unlicensed Wireless Broadband”, Nov 18, 2005, New America Foundation
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 17
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Submission
Channel Bonding
• Make opportunistic and simultaneous use of multiple contiguous TV channels
• Benefits:– More data rate or range
• Initial link-budget analysis showed that single-TV channel can not support full data rate (e.g., 18Mbps) upto 30 Km range
– Multi-path Diversity• Small BW signal can have deep fade or flat fade
• Wider-bandwidth signal provides more frequency/multipath diversity
– Interference• Wider-band reduces the amount of interference
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 18
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Submission
Channel Bonding: Capacity
• Aggregate TV channels to get more capacity– Shannon: C = B.log2(1+S/N)
– capacity proportional to BW, but logarithmic with SNR or signal power
• If S/N is fixed, then capacity increases linearly with bandwidth
• If signal power is fixed, but bandwidth is increased– C = B.log2(1+S/(BNo))
– Capacity still increases as bandwidth is increased
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 19
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Submission
Capacity of aggregated channels as a given signal power is spread over more channels
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 20
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Submission
Preliminary Link Budget (LOS)
modulation QPSK 64-QAM 16-QAMcoding rate 1/2 2/3 1/2Throughput/channel 5 19 29 Mb/scenter frequency 0.7 0.7 0.7 GHzbandwidth 6 6 18 MHzDistance 30000 6000 30000 mTx power 4 4 4 WTx averg power 36.0 36.0 36.0 dBmTX antenna gain 0.0 0.0 0.0 dBiRx powerfree space path loss 119 105 119 dBRx antenna gain 12 12 12 dBicable and other losses 3 3 3 dBTotal received avrg power -74 -60 -74 dBmReceiver noise figure 4 4 4 dBNoise power -106 -106 -101 dBmInterference allowance 3 3 3 dBReceived SNR 25 39 21 dBRequired SNR 4 25 10 dBImplementation/OFDM loss 6.0 6.0 6.0 dBLink Margin 15.4 8.3 4.6 dB
• Difficult to achieve 19Mbps over 30Km
• channel bonding needed to achieve long range
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 21
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Submission
Channel Bonding Scheme
• 6, 12, 18 MHz channels
• Constant inter-carrier spacing
• Depends on availability
• Several receiver techniques to deal with flexible BW– Selectable analog filters
– Up sampling digital filters
TVTV
WRAN
N N+1 N+2N-1N-2 N+4N+3N-3
TVTV
WRAN
N N+1 N+2N-1N-2 N+4N+3N-3
TVTV
WAN
N N+1 N+2N-1N-2 N+4N+3N-3
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 22
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Submission
Channel bonding structure
• 6K FFT over 3 TV channels– 2K per TV channel
– Null out the outer carriers for 1 or 2 TV channels
• Fixed inter-carrier spacing– Several implementation
possibilities
DataSub-carrier
PilotSub-carrier
Guard/NullSub-carrier
6 MHz
18 MHz
12 MHz
DC
DC
DC
12 MHz
6 MHz
18 MHz
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 23
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Submission
FFT Mode for WRAN Systems
No. of Bonded Channel
Basic FFT Mode
1 2 3
1K 1K 2K NA
2K 2K 4K 6K
4K 4K NA NA
6K 6K NA NA
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 24
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Submission
Superframe Structure
Superframe n-1 Superframe n Superframe n+1 ...Time
...
Preamble SCH frame 0 frame 1 frame m...
TV Channelt-1
TV Channelt
TV Channelt+1
Time
Preamble SCH
Preamble SCH
Fre
qu
en
cy
Preamble SCHFrame
0Frame
1
Framem-2
(Quiet)...
... Frame0
Frame1
Preamble SCH
Preamble SCH
Occupied by Incumbent
Occupied by Incumbent
Framen
Occupied by Incumbent
Framem
Framem-1
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 25
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Submission
Preamble
• Superframe preamble – Over 1512 sub-carriers (every fourth or second non-zero),
– 5 MHz BW
– Simply duplicate for additional TV channels
– 1 MHz gap between adjacent channels to relax filtering
– 2 symbol duration (1 more for data)
• Frame preamble: 1-3 TV channels – 1728*N sub-carriers
– Short preamble is optional
ST1 ST5ST4ST3ST2 LT1 LT2GI
TSYMTSYM
(short) (long)
Example structure
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 26
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Submission
Preamble
• Preamble has the repetition pattern in the time domain:
– Time synchronization
– Frequency synchronization
– Channel estimation
– Cell ID detection
• Preamble is modulated using BPSK modulation.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 27
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Submission
Transformed QPSK/OFDMA
• Spread data over some sub-carriers (QPSK only)– Hadamard– Two-carrier– FFT based unitary pre-coding– Frequency offset DFT
• Depending on the receiver structure, this can– Increase capturing of multipath
diversity– Increase resiliency
to interferers• Receiver structures
– MMSE– Approximate ML
dev 1(64QAM)
dev3
dev5 (16QAM)
Dev4 (S-QPSK)
Dev2 (16QAM)
Dev7 (S-QPSK)dev6 (64QAM)
Dev8(64QAM)
1234
Time (in OFDM symbol unit)
subchannels
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 28
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Submission
OFDMA Parameters/Single Channel (6MHz)
Mode 1K 2K 4K 6K
FFT Size 1024 2048 4096 6144
Bandwidth(k = 1, 2, …, 6)
k MHz
Sampling Factor 8/7
No. of Used Subcarriers(including pilot, but not DC)
140 * k 280 * k 560 * k 840 * k
Sampling Frequency 48/7 MHz
Subcarrier Spacing 6.696 kHz(***) 3.348 kHz 1.674 kHz 1.116 kHz
Occupied Bandwidth 6.696 kHz*140*k 3.348 kHz*280*k 1.674 kHz*560*k 1.116 kHz*840*k
Bandwidth Efficiency(*) 93~94 %
FFT Time 149.33 us 298.66 us 597.33 us 896 us
Cyclic Prefix Time(**) 37.33 us 74.66 us 149.33 us 224 us
OFDMA Symbol Time 186.66 us 373.33 us 746.66 us 1120 us
(*) Bandwidth Efficiency = Subcarrier Spacing * (Number of Used Subcarriers + 1)/BW(**) It is assumed that cyclic prefix mode is 1/4.(***) Italics indicate an approximated value.
March 2006
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Slide 31
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Submission
OFDMA parameters – channel bonding
Parameter3 TV bands 2 TV bands 1 TV bands
18 21 24 12 14 16 6 7 8
Inter-carrier spacing,
F (Hz)3348 3906 4464 3348 3906 4464 3348 3906 4464
FFT period, TFFT (s) 298.66 256.00 224.00 298.66 256.00 224.00 298.66 256.00 224.00
Total no. of sub-carriers,
NFFT
6144 4096 2048
No. of guard sub-carriers,
NG (L, DC, R)1104 (552,1,551) 736 (368,1,367) 368 (184,1,183)
No. of used sub-carriers,
NT = ND + NP
5040 3360 1680
No. of data sub-carriers, ND 4680 3120 1560
No. of pilot sub-carriers, NP 360 240 120
Occupied bandwidth (MHz) 16.884 19.698 22.512 11.256 13.132 15.008 5.628 6.566 7.504
Bandwidth Efficiency (%) 93.8
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 32
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Submission
Data Rate• Bandwidth = 6 MHz
• FFT size = 2048
• Cyclic prefix mode = 1/4
• No pilot, no quiet periods assumed
Code Rate
Modulation7/8 5/6 3/4 2/3 1/2
64QAM 23.63 22.50 20.25 18.00 13.50
16QAM 15.75 15.00 13.50 12.00 9.00
QPSK 7.88 7.50 6.75 6.00 4.50
Unit: Mbps
Data Rate = No. of used subcarriers * code rate * no. of bits per modulation symbol/OFDM symbol time
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 33
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Submission
Data Rate – Channel Bonding• Bandwidth = 3*6 MHz
• FFT size = 2048
• Cyclic prefix mode = 1/4
• No pilot, no quiet periods assumed
Code Rate
Modulation7/8 5/6 3/4 2/3 1/2
64QAM 70.89 67.50 60.75 54.00 40.50
16QAM 47.25 45.00 40.50 36.00 27.00
QPSK 23.64 22.50 20.25 18.00 13.50
Unit: Mbps
Data Rate = No. of used subcarriers * code rate * no. of bits per modulation symbol/OFDM symbol time
* no. of channel bonded
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 34
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Spectral Efficiency
Code Rate
Modulation7/8 5/6 3/4 2/3 1/2
64QAM 3.94 3.75 3.38 3.00 2.25
16QAM 2.63 2.50 2.25 2.00 1.50
QPSK 1.31 1.25 1.13 1.00 0.75
Unit : bps/Hz
Spectral Efficiency = No. of used subcarrier*code rate*no. of bits per modulation symbol/OFDM symbol time/BW
• Single channel bandwidth = 6 MHz
• FFT size = 2048
• Cyclic prefix mode = 1/4
• No pilot, no quiet periods assumed
• The spectral efficiency is same for all fractional BW mode
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 35
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Submission
Minimum Peak Throughput per CPE
Code Rate
Modulation7/8 5/6 3/4 2/3 1/2
64QAM 2.15 2.05 1.84 1.64 1.23
16QAM 1.43 1.36 1.23 1.09 0.82
QPSK 0.72 0.68 0.61 0.55 0.41
Unit : Mbps
Min. Peak Throughput = No. of used subcarriers*code rate*no. of bits per modulation symbol/OFDM symbol time/no. of CPE’s
• Bandwidth = 6 MHz• FFT size = 2048• Cyclic prefix mode = 1/4• No. of CPE’s = 512 CPE’s/oversubscription ratio 50 ~ 11 CPE’s• No pilot, no quiet periods assumed
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 36
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Submission
Fractional BW Usage
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 37
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Submission
Fractional Bandwidth Usage
• If wireless microphones are in operation in TV channel, the WRAN systems may be clear the entire TV channel
• The number of used sub-carriers is proportional to the fractional bandwidth
• The fractional BW mode is identified by using a Preamble
• Example:
6 MHz Unused(6 MHz)6 MHz
f
Incumbent or other CR user(except microphone user)TV channel Microphone user
Fractional useof TV channel
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 38
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Submission
Fractional Bandwidth Mode
• Total Number of Fractional BW Mode To Detect : 36
1 2 3 4 5 6 7 8
1
2
3
4
5
6
7
8
Start position of fractional BW mode
Fra
ctio
nal
BW
12345678
Fra
ctio
nal B
W o
f 1
MH
z
Null
Null
Real B
W o
f 8
MH
z
Start positionof fractional BW mode
Fractional BWmode zone
Not applicable
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 39
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Submission
Preamble Sequence for Fractional BW Usage (2K FFT)
Index Fractional BW Start Position PN Sequence (1680 bits)
0 1 0
0x251D994101EDA04D8BD0B8EA6FA20AE590C2CC199AB083C6AE61F091F2DD41D989EC164B1481D611BE9CEA0094AFE9DB56A4763F55B26E54EAB73ACD7D4BBA64C1421BC3EB9D67113A5FB9C529AADC9CAB1FB882905601778659CDB69AFCBADDF8B42314A7985B5F87C20692309D350454FF9326481683FADAE4711DD0CC5DACEDF7CD5DF1177D60EBA4DBE657F19F08189EFC6B5DE6C2CFDCD13195DE077586B8EE01E00B6468B10A53FAAC1DD846E2A01681980D444B6AD0D34C34EC9CFD9341507878EC9FBAE498F5A20614BDF3E4B22D
1 1 1
2 1 2
3 1 3
4 1 4
5 1 5
6 1 6
7 1 7
8 2 0
9 2 1
10 2 2
11 2 3
12 2 4
13 2 5
14 2 6
… … … …
33 7 1
34 7 2
35 8 1
This sequence will be determined to minimize
the PAPR
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 40
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Submission
Flow Diagram of Fractional BW Mode Detection
CPE Power On Fractional BW ModeDetection
Using Preamble
Decoding SuperframeControl Header (SCH)
Fractional BWUsage Mode
Decoding Frame
Synchronization &Channel Estimation
Superframe PreambleStart Position Detection
Signal Detection &Automatic Gain Control
Channel Bonding
Information
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 41
doc.: IEEE 802.22-06/0005r5
Submission
Simple Mode Detection Procedure (1)
CPEPower On
Searchthe Fractional BW
Usage Mode(Correlation with
All PreambleSequence)
Confirmthe Fractional BW
Usage Mode(Correlation with
Previous PreambleSequence)
CorrelationOut>TH?YES
NO
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 42
doc.: IEEE 802.22-06/0005r5
Submission
Simple Mode Detection Procedure (2)
• Example:
TransmittedSuperPreamble
Index
CorrelatedSuperPreamble
Index
DetectedSuperPreamble
Index
0 0 … 0 17 17 … 17 31 31 … 31 25 25 …
All 0 … 0 0 17 … 17 17 31 … 31 31 25 …
0 0 … 0 17 17 … 17 31 31 … 31 25 25 …
The Correlation Out is less than the Threshold
Search all fractional mode again
Fractional mode changed
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 43
doc.: IEEE 802.22-06/0005r5
Submission
Subchannelization
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 44
doc.: IEEE 802.22-06/0005r5
Submission
Symbol Structure For AMC/Diversity Subchannel
• The concept of AMC subchannel is same to that of 802.16-2004
• The concept Diversity subchannel is same to the DL optional FUSC of 802.16-2004
• Just the number of used subcarriers is different
– 802.16e: no. of subchanel=32, no. of subcarriers per subchannel=54
– 802.22: no. of subchanel=30, no. of subcarriers per subchannel=56
• So the basic permutation sequence will be slightly modified
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 45
doc.: IEEE 802.22-06/0005r5
Submission
Pilot Pattern Design (1)
• Pilot pattern is varied with channel condition
• Pilot pattern is controlled by adjusting the pilot symbol interval and pilot subcarrier interval
• A robust channel parameter estimation is required for reliable pilot design
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 46
doc.: IEEE 802.22-06/0005r5
Submission
Pilot Pattern Design (2)• RMS delay spread of WRAN profile (Approximated)
• Pilot subcarrier interval can be determined as follows– Pilot subcarrier interval*subcarrier spacing < coherent bandwidth
Multipath ProfileParameters A B C D
CoherentBandwidth
(kHz)
90% 28.90 23.61 18.63 3.38
50% 289.02 236.13 186.39 33.80Pilot
SubcarrierInterval
90% 8.63 7.05 5.56 1.00
50% 86.32 70.52 55.67 10.09
1) We assume that the BW is 6 MHz and FFT mode is 2K.2) 90% coherent BW=1/(50*rms delay spread), 50% coherent BW=1/(5*rms delay spread)
Multipath Profile A B C D
RMS Delay Spread 692 ns 847 ns 1073 ns 5917 ns (*)
(*) We assume that the 6-th path has the excess delay of 60 ns and relative amplitude of -10 dB
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 47
doc.: IEEE 802.22-06/0005r5
Submission
Pilot Pattern Design (3)• Coherent Time
– 1/fm, where, fm is the maximum doppler shift
• Pilot symbol interval can be determined as follows– Pilot symbol interval*OFDMA symbol time < coherent time
Multipath ProfileParameters A B C D
Maximum Doppler Shift (Hz) 2.5
Coherent Time (sec) 0.4
Pilot Symbol Interval 1071.4
Here, we assume that the BW is 6 MHz, FFT mode is 2K, and GI mode is 1/4.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 48
doc.: IEEE 802.22-06/0005r5
Submission
Pilot Pattern For AMC Subchannel
• Typical BIN structure– Set of 14 contiguous subcarriers within an OFDMA symbol
• AMC subchannel consists of 4 contiguous bins
12 Data Subcarriers
2 Pilot Subcarriers
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 49
doc.: IEEE 802.22-06/0005r5
Submission
Pilot Pattern For Diversity Subchannel
• All the pilot subcarriers are allocated first• And then the remaining subcarriers are used
exclusively for data transmission• Number of used subcarriers are divided into 14
contiguous subcarriers in which two pilot subcarriers are allocated
• The position of the pilot subcarriers in 14 contiguous subcarriers varies according to the index of OFDMA symbol which contains the subcarriers
• Pilot subcarrier index:– k : pilot subcarrier index, 0,…,239 for 2K mode– m : [symbol index] mod 3
137 mk
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 50
doc.: IEEE 802.22-06/0005r5
Submission
Advanced Channel Coding
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 51
doc.: IEEE 802.22-06/0005r5
Submission
Channel Coding
• Coding Scheme– Mandatory: Convolutional Code -> similar to 802.16
– Optional:• Duo Binary Turbo Code
• LDPC Code (IEEE 802.16e LDPC) New
• Shortened block turbo code New
– Optional advanced codes currently undergoing cross-simulations• Will compare results and select best optional code(s)
• Selected Code Rates– R = 1/2, 2/3, 3/4, 5/6
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 52
doc.: IEEE 802.22-06/0005r5
Submission
Duo-Binary Turbo-Code Summary
• Excellent performance for wide range of blocks– Have optimized parameters for blocks from 6 bytes to 240 bytes
• Highly flexible scheme– Same encoder/decoder for all blocksizes/coding rates
• Reasonable complexity– ~35% decrease in complexity/decoded bit compared to Binary TC.
• Mature Technology
• Code Reuse/ Already in following standards– IEEE 802.16 / WiMAX; HomePlug, DVB-RCS, DVB-RCT,
ETSI HIPERMAN
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 53
doc.: IEEE 802.22-06/0005r5
Submission
Low-Density Parity-Check Codes
• Motivation for LDPC– Near capacity performance
– High-throughput low-complexity implementation
– Code reuse between 802 specifications
• Features of IEEE 802.16e LDPC codes– Compact representation of code matrices
– Simplified structured encoder/decoder architecture across all code rates
– Low-complexity differential-style encoding
– Enhanced Layered Decoding to reduce the number of iterations
– Special design feature in rate 1/2, 2/3 code provides further throughput doubling in layered decoding
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 54
doc.: IEEE 802.22-06/0005r5
Submission
LDPC Code Reuse Within 802• LDPC codes adopted in DVB-S2, 802.16e, 802.11n• IEEE 802.16
– Initial WiMax profile includes• CC and CTC, Chase Combining HARQ for CTC
– Future WiMAX profiles likely to include…• CTC with incremental redundancy (IR) HARQ
– IR may add little value for fixed access
• LDPC with Chase Combining– Missed first profile due to time-to-market considerations
• IEEE 802.11n– IEEE 802.16e-style LDPC codec adopted as the only
advanced channel coding scheme in January 2006 joint proposal
• Selecting LDPC for 802.22 would lead to additional reuse
to/from indoor
antenna
802.22 radio
802.11n radio
Common baseband elements
to/from rooftop antenna
ethernet
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 55
doc.: IEEE 802.22-06/0005r5
Submission
Shortened Block Turbo Code (SBTC)
• Turbo product code (TPC) is an advanced coding option in 802.16
• STBC is an improved form of TPC– SBTC has lower decoding complexity than TPC without
performance loss
• Component code – Extended Hamming code
• Native code: (16,11), (32,26) and (64,57)• Other code rate through shortening
– Parity check code• (8,7) and (16,15)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 56
doc.: IEEE 802.22-06/0005r5
Submission
Parity Check Matrices for Hamming Codes
154111000
111000
110110
101101
315111000
111000
111000
110110
101101
636111000
111000
111000
111000
110110
101101
N’ = 15K’ = 11
N’ = 31K’ = 26 N’ = 63
K’ = 57
Special parity check matrix design simplifies the decoding complexity.The syndrome value gives the error position, thus, look-up table is not needed.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 57
doc.: IEEE 802.22-06/0005r5
Submission
Multiple Antennae Options
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 58
doc.: IEEE 802.22-06/0005r5
Submission
Multiple Antenna Options
– Equal Gain Transmit Beamforming Using Codebooks.
– Downlink Closed Loop SDMA.
– Adaptive Beam-Forming Techniques.
– Space Time Block Coding (STBC).
– Combined Diversity/Spatial multiplexing/Delay Management.
– Uplink “Virtual” SDMA MIMO.
Multiple antennae techniques offer various advantages in various scenarios, including inherent benefits for the protection of incumbents. We are studying the following options. Final decisions on which ones are included will be based on performance and complexity.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 59
doc.: IEEE 802.22-06/0005r5
Submission
Equal Gain Transmit Beamforming
• When multiple antennae are used for transmission, it is very important to have equal gain transmissions from each antenna, especially when used with OFDM.
• Eigen-beamforming, when used in an asymmetrical situation (NT > NR), DOES NOT guarantee equal power.
• Single-stream or multiple stream transmission is proposed
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 60
doc.: IEEE 802.22-06/0005r5
Submission
Quantized Equal Gain Beamformer For Single Stream
• NT transmit antennae and NR receive antennae (NR could be 1).• Objective: find quantized beamformer Q (NT X 1).• Method:
– All entries of Q are restricted to be – First entry is fixed at 1+ j– Q is picked to maximize– No. of bits required to specify Q: 2*(NT -1) per frequency bin.– If p consecutive frequencies are grouped, Q is picked to maximize
– e.g: 2x1 beamformer, grouping 4 tones over 64 tones bandwidth would require only 4 bytes of feedback, with ~ 1dB degradation.
• Multiple streams: find multiple beamformers of that form for the simultaneous transmission of multiple streams to 1 user
j1
QHHQ HH
iiHi
Hi
p
iQHHQ
1
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 61
doc.: IEEE 802.22-06/0005r5
Submission
Quantized Equal Gain BeamformerPerformance Summary
• Performance summary was presented in January 2006 [doc.: IEEE 802.22-06/0005r1]
• Very simple and efficient codebook based beamforming, ensuring equal gain transmissions.
• About 6 –7dB downlink gain with 2 transmit antennae.• About 11-12dB downlink gain with 4 transmit antennae.
• Similar gains on uplink, with receive-diversity at base-station.
• Gains can be realized with about 4 bytes of feedback per user for 2 transmit antennae and 12 bytes per user for 4 transmit antennae.
• CPE could have more receive antenna than transmit antennae, for added performance, without changing the feedback requirements.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 62
doc.: IEEE 802.22-06/0005r5
Submission
Downlink Closed-Loop SDMA (CL-SDMA)Linear processing with downlink channel sounding
• Throughput performance was presented in January 2006 [doc.: IEEE 802.22-06/0016r1]
• Very large throughput can be achieved by the use of reliable channel state information at the transmitter in slowly fading channels, to allow for coordinated beamforming between the transmitter and the receivers
• Practical implementation:– In FDD or TDD: CL-SDMA Mode 1 (2 base station antennas)
No channel reciprocity requirement: finite-rate quantized feeedback– In TDD: CL-SDMA Mode 2 (2 or more base station antennas)
Requires channel reciprocity: direct uplink sounding
• Use on adjacent permutation subcarriers with multiuser diversity
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 63
doc.: IEEE 802.22-06/0005r5
Submission
CL SDMA Overview
The Base Station has N transmit antennas, and uses N beamforming vectors M1 … MN
CPEs have N or more receive antennas, and use beamforming vectors W1 , W2 … WN
CL SDMA Mode 1 is only applicable with N = 2 transmit antennas.
xk
x1
xN
W1*
x1 estimate
Wk*
xk estimate
WN*
xN estimate
Base station transmitter
downlinktransmission
M1
Mk
MN
1
2
k
N
CPE receivers
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 64
doc.: IEEE 802.22-06/0005r5
Submission
Base Station Transmitter and CPE Receiver Structures
Channel Encoder
QAM Modulation X
X +
+
OFDMModulation 1
Channel Encoder
QAM Modulation X
XOFDM
Modulation 2
User 1Data Packet
User 2Data Packet
M1,1
M1,2
M2,1
M2,2
1
2
OFDMDemodulationX
+
W*k,1
OFDMDemodulationX
W*k,2
NOFDM
DemodulationX
W*k,N
Channel Decoder
User k decodedData Packet
MMSE or ZF per tone
QAM demodulator
Receiver or user k
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 65
doc.: IEEE 802.22-06/0005r5
Submission
Adaptive Beam-Forming
• Adaptive beam-forming (ABF) for 802.22 systems:
– Mitigate co-channel interference (CCI) inherent to OFDMA systems
– Since all CPEs are fixed at known locations, their directions-of- arrival (DOAs) may easily be obtained at the BS.
– Large cell in 802.22 networks also makes beam-forming problem simple from 2D to 1D problem: easy DOA estimation.
– With the transmit and/or receive diversity, adaptive beam-forming may significantly increase the cell radius.
• More efficient than fixed-beam array
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 66
doc.: IEEE 802.22-06/0005r5
Submission
Adaptive Beam-Forming Algorithms
• DOA Based Sample Matrix Inversion (SMI) Algorithm
where is the steering vector for incident angle and is the estimated interference-plus-noise covariance matrix.
• Reference Signal Based SMI Algorithm
where is the correlation vector and is the estimated covariance matrix.
– Reference signal is required!
1ˆˆ u w R a
a
1ˆ ˆˆ x xdw R r
ˆuR
ˆxRˆxdr
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 67
doc.: IEEE 802.22-06/0005r5
Submission
Adaptive Beam-FormingPerformance Summary
• Performance summary was presented in January 2006 [doc.: IEEE 802.22-06/0005r1]
• Efficient CCI cancellation by simple adaptive beam-forming algorithms
• In uplink, the reference signal method seems more effective due to
– Simplicity in implementation
– Robustness to calibration errors due to self-healing nature
– However, in case of a very large delay spread, the DOA based approach seems preferable.
– Selective usage according to environments may be necessary.
• In downlink, the DOA based adaptive beam-forming seems more desirable.
– Robustness to calibration errors in downlink
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 68
doc.: IEEE 802.22-06/0005r5
Submission
Figure. Block diagram of an STBC-OFDM system
Cyclic prefix
RemovalFFT P/S
Linear Combiner
Data demapping
Binary output data
Data mapping
S/P STBCEncoding
IFFT
IFFT
Cyclic prefix
Cyclic prefix
Binary input data
1~ 4h
General STBC
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 69
doc.: IEEE 802.22-06/0005r5
Submission
STBCPerformance Summary
• Performance summary was presented in January 2006 [doc.: IEEE 802.22-06/0005r1]
• 2K FFT OFDMA, 2 OFDM symbols preamble, and channel estimation– Partitioned MMSE estimation performed by using the preamble– SNR in MMSE: 20dB– RMS delay parameter in MMSE: 9s
• About 3 –7dB downlink gain for =0.7, when employing (2 x 1) STBC scheme.
• Additional ~2.5dB gain when employing (2 x 1) closed loop transmit diversity.
• Even in a highly correlated case, for example =0.9, the performance improvement is rather significant.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 70
doc.: IEEE 802.22-06/0005r5
Submission
Full Diversity Full Rate Scheme
• While Space-Time Coding (STC) aims for transmit diversity gain, Spatial Multiplexing (SM) increases the throughput in MIMO channels.
• Full Diversity Full Rate (FDFR) schemes strike both the diversity and multiplexing at the same time.
• In FDFR, complexity at the receiver is much higher than SM.
• We propose a scheme, which facilitates successive interference cancellation at the receiver with slight loss in rate.
• Thus, the proposed scheme is FD but almost FR.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 71
doc.: IEEE 802.22-06/0005r5
Submission
Basic Transmit Beamforming (BTB)
• In DL, beamformer only directs transmission to the path/cluster with the strongest gain per user.
• Other directions are suppressed – reducing overall delay
• Frequency domain beamforming for each user (subchannel) – different directions
.
.
.
Ant NT
Ant 1
.
.
.
User K
User 1
MOD Frequency Domain
Beamformer
MOD
Frequency Domain
Beamformer
Windowing & Pulse Shaping
OFDMA Formulator
OFDMA Formulator
Windowing & Pulse Shaping
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 72
doc.: IEEE 802.22-06/0005r5
Submission
Transmit Beamforming with Diversity/Spatial Multiplexing
• In DL, beamformers direct transmission several pathss/cluster
• Uncorrelated eigen-channels may be used for diversity transmission (CDD) or spatial multiplexing.
.
.
.
Ant NT
.
.
.
Ant 1
Channel Coded Bits of User 1
MOD
Frequency Domain
BF 2, User 1
OFDMA Formulator
Windowing & Pulse Shaping
Phase Shifter, User 1
Frequency Domain
BF 1, User 1
Vec tor Adder
Channel Coded Bits of User L
MOD
Frequency Domain
BF 2, User L
OFDMA Formulator
Windowing & Pulse Shaping
Phase Shifter, User L
Frequency Domain
BF 1, User L
Vec tor Adder
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 73
doc.: IEEE 802.22-06/0005r5
Submission
Beamforming with Channel Delay Management
By adjusting timings D1 and D2, the overall delay of the channel can be changed.
Reflector 1Or repeater
Reflector 2Or repeater
CPE
Rich local scatters
Beam 1
Beam 2
Delay 1 T1 = τ1+ D1
Delay 2 T2 = τ2+ D2
Overall Delay|T1-T2| +δ
Pre-alignment& beamforming
Stream 1
Stream 2
When the overall channel delay exceeds the cyclic prefix period, spatial resolution of multipaths in the angular domain allows to alleviate the inter-block interference.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 74
doc.: IEEE 802.22-06/0005r5
Submission
Uplink SDMA(formerly Virtual MIMO)
• Uplink
• Multiple Antennas at BS and single antenna at each CPE
• Multiple CPEs share the same physical channel
• Spectrum efficiency increase linearly with CPE number if the CPE number is less than the number of BS antennas
CPE 1
CPE 2
Base
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 75
doc.: IEEE 802.22-06/0005r5
Submission
IEEE 802.16e Uplink Channel Sounding
• Presented in January 2006: 22-06-0013-00-0000_Uplink_Channel_Sounding.ppt• ULCS is a means of providing channel response information to the BS on an as-needed basis
– CPE transmits sounding waveform on the UL to enable the BS to measure the channel response– Intended for TDD systems where UL&DL RF reciprocity can be leveraged
• ULCS enables Closed-Loop Transmit Antenna Array Techniques on the DL in TDD:– Baseband digital transmit beamforming– Transmit Spatial Division Multiple Access (SDMA)– Closed-loop Multiple Input Multiple Output (MIMO)
• ULCS provides an easier and better-performing alternative to other 802.16e Closed-Loop techniques with minimal added complexity to the CPE
– Lower channel measurement delay– Better frequency-response tracking
• Future-Proof: Transmit array algorithms can be upgraded at the BS with no impact on CPE– Technique is independent of the number of BS antennas
• Handles asymmetric bandwidth occupancy of UL&DL transmissions
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 76
doc.: IEEE 802.22-06/0005r5
Submission
Multiple antennas on-going work
• A spatial channel model for the WRAN is currently under development by the joint proposers.
• Supporting features, such as uplink channel sounding, specific preamble design, MAC messages.
• Performance evaluation and selection of the proposed schemes.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 77
doc.: IEEE 802.22-06/0005r5
Submission
Spectrum Sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 78
doc.: IEEE 802.22-06/0005r5
Submission
Spectrum Sensing : Fact
• Spectrum sensing should be accurate enough to protect incumbent users
• Spectrum sensing should be fast enough to support the sensing protocol in MAC
• Spectrum sensing block should be able to be implemented by reasonable cost/resources
• “Spectrum sensing technology” is implementation technology.
• There is no single sensing technology can meet all the sensing requirement.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 79
doc.: IEEE 802.22-06/0005r5
Submission
Spectrum Sensing : What we proposed
• We proposed a “sensing system architecture”, not an individual sensing technology, which we believe is the most efficient way to support MAC while sustain accuracy.
• Within this system architecture, multiple sensing technologies can be chosen to meet the sensing requirements (time, sensitivity) by the manufacturer
• We’ve been trying to include various sensing technologies for primary user group to feel comfortable on WRAN
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 80
doc.: IEEE 802.22-06/0005r5
Submission
Sensing Receiver Architecture
MAC
Fine/Feature
RFE
Energy Detection
Omni Antenna
Control
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 81
doc.: IEEE 802.22-06/0005r5
Submission
Spectrum Sensing Strategy
Energy Detectionfor wide band
(Analog, RSSI, MRSS, FFT…)
Begin Sensing
Fine/Feature Detection for single channel
End Sensing
occupied?Y
N
MAC(Select
single channel)
FFT CSFDField Sync
OptimumRadiometer
Multi-cycleDetector
AACSpectral
Correlation
Spectrum Usage
Database(BS) ATSC
Segment Sync
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 82
doc.: IEEE 802.22-06/0005r5
Submission
List of sensing techniques included in the proposal
• Energy detection– Analog integrator
– MRSS (Samsung/GT)
– RSSI (Philips)
– FFT
• Fine/Feature Detection– Cyclo-Stationary Feature Detection (Samsung)
– Field-sync detection (Philips)
– ATSC Segment Sync (Thomson)
– FFT based (Philips and Huawei)
– Optimum radiometer (France Telecom)
– Multi-cycle detector (France Telecom)
– Analog Auto-Correlation (Samsung/GT)
– Spectral correlation (Huawei)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 83
doc.: IEEE 802.22-06/0005r5
Submission
Spectrum Sensing : What we will do
• Each of the sensing technology will be rigorously evaluated by the procedure to be defined.
• Individual sensing technologies that pass the evaluation process shall be included the draft as an optional.
• Our proposal is open to new innovative sensing technology.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 84
doc.: IEEE 802.22-06/0005r5
Submission
Backup Slides
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 85
doc.: IEEE 802.22-06/0005r5
Submission
Equal Gain Beamformer For Multiple Streams
• Let received vector be: – NT: No. of transmit antennae.– NR : No. of receive antennae (assumed here to be = no of streams)– H is the channel matrix (NR X NT),– Q is the beamforming matrix (NT X NR).– x is the data vector (NR X 1),
• Transmitted vector: • Equal-gain constraint implies that each row of Q has the same
power.• Let H = USVH be the SVD of H. • Then, if NT = NR, and Q = V, we get equal gain beamforming
because V is an orthonormal matrix.• If NT > NR, and Q = V(:, 1:NR), then each row of Q does not have
the same power => unequal gains.
nxHQr
xQy
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 86
doc.: IEEE 802.22-06/0005r5
Submission
Quantized Equal-Gain Beamformer Simulation Scenario
• 2K FFT, 64 tones per user, all tones used for data transmission. ¼ cyclic prefix.
• Subchannelization: 16 groups of 4 tones, equally spaced over 6 MHz bandwidth. Each packet simulated had a randomly generated subcarrier set.
• Channel: 2sec RMS delay spread (total impulse response spread = 20sec), exponential Rayleigh fading, uncorrelated channels from each antenna.
• 1000 byte packets, each packet goes through a different channel realization, simulation run until 100 packet errors are accumulated.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 87
doc.: IEEE 802.22-06/0005r5
Submission
Quantized Equal-Gain Beamformer Performance
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 88
doc.: IEEE 802.22-06/0005r5
Submission
CL SDMA Flowchart
CSI = channel state informationCQI = channel quality indicator
Base station CPE
TDD: uplink sounding pilots and CQI feedback
Downlink sounding pilots and data
Downlink pilots
Channel estimation and computation of CQI
Computation of transmit filters
Computation of receive filters and data detection
FDD: Quantized CSI and CQI feedback
(FDD: additional quantized CSI)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 89
doc.: IEEE 802.22-06/0005r5
Submission
Performance of downlink closed-loop SDMA with correlated fading at the transmitter
3GPP LTE suburban-macro small-scale fading channel model (mean CINR = 7.5 dB)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 90
doc.: IEEE 802.22-06/0005r5
Submission
Adaptive Beam-Forming (2)
• Adaptive array vs. Fixed-beam array– More Efficient CCI Suppression: Adaptive array system steers the
main beam to the direction of a desired signal, while steering nulls to the directions of undesired signals.
Figure. Adaptive array vs. fixed-beam array
1st co- channel interferer
desired signal
2nd co- channel interferer
fixed-beam adaptive array
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 91
doc.: IEEE 802.22-06/0005r5
Submission
ABF Performance Evaluation
• Antenna Array– Array type: Linear equi-spaced array with half wavelength spacing
consisting of 8 antenna elements.
– Root-MUSIC is used to estimate the DOAs of incident signals.
– All incident signals are assumed to have zero elevation angle.
• Angular Spread– Laplacian model– All clusters are assumed to have the angular spread of 0.3o.
• Others– No. of OFDM symbols for reverse link preamble is 1.
– No. of sub-carriers assigned to users is 256.
– No. of sub-carriers per sub-band is 16 for reference signal method.
– No channel coding employed
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 92
doc.: IEEE 802.22-06/0005r5
Submission
0.83 secrms delay
0.68 secrms delay
18.0o-11.2o9.5o-6.9o2.6o0oIncident angles*
12.0o-8.6o6.0o-4.3o2.6o0oIncident angles*
0.37 Hz0.17 Hz2.5 Hz0.13 Hz00.1 HzDoppler frequency
-20 dB-16 dB-22 dB-7 dB0-6 dBRelative amplitude
11 sec7 sec4 sec2 sec0-3 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE B
0.37 Hz0.17 Hz0.13 Hz2.5 Hz0.10 Hz0Doppler frequency
-19 dB-24 dB-22 dB-15 dB-7 dB0Relative amplitude
21 sec13 sec11 sec8 sec3 sec0Excess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE A
0.83 secrms delay
0.68 secrms delay
18.0o-11.2o9.5o-6.9o2.6o0oIncident angles*
12.0o-8.6o6.0o-4.3o2.6o0oIncident angles*
0.37 Hz0.17 Hz2.5 Hz0.13 Hz00.1 HzDoppler frequency
-20 dB-16 dB-22 dB-7 dB0-6 dBRelative amplitude
11 sec7 sec4 sec2 sec0-3 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE B
0.37 Hz0.17 Hz0.13 Hz2.5 Hz0.10 Hz0Doppler frequency
-19 dB-24 dB-22 dB-15 dB-7 dB0Relative amplitude
21 sec13 sec11 sec8 sec3 sec0Excess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE A
(* : defined for adaptive beam-forming)
Channel Parameters for ABF Simulation (1)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 93
doc.: IEEE 802.22-06/0005r5
Submission
Channel Parameters for ABF Simulation (2)
5.36 secrms delay
1.07 secrms delay
15.0o-11.2o7.7o-3.0o-0.86o0oIncident angles*
13.0o-10.3o7.7o-3.0o-0.86o0oIncident angles*
0.13 Hz0.17 Hz2.5 Hz0.1 Hz00.23 HzDoppler frequency
-7 dB-21 dB-18 dB-22 dB0-10 dBRelative amplitude
28 sec22 sec16 sec5 sec0-2 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE D
0.10 Hz0.23 Hz2.5 Hz0.17 Hz00.13 HzDoppler frequency
-16 dB-24 dB-14 dB-19 dB0-9 dBRelative amplitude
33 sec24 sec16 sec5 sec0-2 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE C
5.36 secrms delay
1.07 secrms delay
15.0o-11.2o7.7o-3.0o-0.86o0oIncident angles*
13.0o-10.3o7.7o-3.0o-0.86o0oIncident angles*
0.13 Hz0.17 Hz2.5 Hz0.1 Hz00.23 HzDoppler frequency
-7 dB-21 dB-18 dB-22 dB0-10 dBRelative amplitude
28 sec22 sec16 sec5 sec0-2 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE D
0.10 Hz0.23 Hz2.5 Hz0.17 Hz00.13 HzDoppler frequency
-16 dB-24 dB-14 dB-19 dB0-9 dBRelative amplitude
33 sec24 sec16 sec5 sec0-2 secExcess delay
Path 6Path 5Path 4Path 3Path 2Path 1PROFILE C
(* : defined for adaptive beam-forming)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 94
doc.: IEEE 802.22-06/0005r5
Submission
Figure. Comparison of BER performance for reverse link (INR = 25dB, interference DOAs =(20o, 30o), relative amplitude = (0dB, -3dB) )
Performance Evaluation : ABF Algorithms (1)
0 5 10 15 20 2510-4
10-3
10-2
10-1
100
Un
cod
ed
BE
R
SNR (dB)
Single AntennaDOA Based Reference Profile A Profile B Profile C Profile D
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 95
doc.: IEEE 802.22-06/0005r5
Submission
Figure. Average output SINR vs. azimuth difference for reverse link ( Profile A, SNR = 15dB, INR = 25dB, relative amplitude = (0dB, -3dB) )
Performance Evaluation : ABF Algorithms (2)
10 15 20 25 30 35 40 45 5012
14
16
18
20
22
24
A
vera
ge
Ou
tpu
t SIN
R (
dB
)
Azimuth Difference (Deg)
DOA Based Algorithm Reference Signal Method
Perfect interference cancellation : Output SINR = 24dB
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 96
doc.: IEEE 802.22-06/0005r5
Submission
Figure. Channel mismatch effect for reverse link ( Profile A, INR = 25dB, interference DOAs = (20o, 30o), relative amplitude = (0dB, -3dB) )
Performance Evaluation : ABF Algorithms (3)
0 5 10 15 20 2510-4
10-3
10-2
10-1
100
U
nco
de
d B
ER
SNR (dB)
No Errors
Amp Error = 10%, Phase Error = 10o
Amp Error = 20%, Phase Error = 20o
Amp Error = 30%, Phase Error = 30o
Dashed line : DOA Based Algorithm Solid line : Reference Signal Method
• Error distribution: truncated Gaussian
• Ref. signal method: insensitive due to self-healing nature
• DOA based method: relatively insensitive
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 97
doc.: IEEE 802.22-06/0005r5
Submission
Figure. Effect of channel mismatch for forward link ( Profile A, INR = 25dB, interference DOAs = (20o, 30o), relative amplitude = (0dB, -3dB) )
Performance Evaluation : ABF Algorithms (4)
0 5 10 15 20 2510-4
10-3
10-2
10-1
100
U
nco
ded
BE
R
SNR (dB)
No Errors
Amp Error = 0.1%, Phase Error = 0.1o
Amp Error = 0.2%, Phase Error = 0.2o
Amp Error = 0.3%, Phase Error = 0.3o
Amp Error = 0.5%, Phase Error = 0.5o
Dashed line : DOA Based Algorithm Solid line : Reference Signal Method
• Error distribution: truncated Gaussian
• Ref. signal method: extremely sensitive
• DOA based method: relatively insensitive
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 98
doc.: IEEE 802.22-06/0005r5
Submission
Figure. BER performance of Alamouti’s scheme in 802.22 environments (QPSK, degree of correlation = 0.7)
Performance gain: 3.7dB ~ 7.5dB at 10-2 ~ 10-3 BER
Performance Evaluation : STBC (1)
0 5 10 15 20 2510-5
10-4
10-3
10-2
10-1
100
Modulation = QPSK No. of Rx Ant = 1 = 0.7
U
nco
de
d B
ER
Eb/No
Alamouti case Profile A Profile B Profile C Profile DNo diversity case Profile A Profile B Profile C Profile D
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 99
doc.: IEEE 802.22-06/0005r5
Submission
Figure. BER performance of Alamouti’s scheme in 802.22 environments (16QAM, degree of correlation = 0.7)
Performance Evaluation : STBC (2)
0 5 10 15 20 2510-5
10-4
10-3
10-2
10-1
100
Modulation = 16QAM No. of Rx Ant = 1 = 0.7
U
nco
de
d B
ER
Eb/No
Alamouti case Profile A Profile B Profile C Profile DNo diversity case Profile A Profile B Profile C Profile D
Performance gain: 3.4dB ~ 7.0dB at 10-2 ~ 10-3 BER
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 100
doc.: IEEE 802.22-06/0005r5
Submission
Figure. BER performance of Alamouti’s scheme in 802.22 environments (64QAM, degree of correlation = 0.7)
Performance Evaluation : STBC (3)
Performance gain: 3.1dB ~ 6.0dB at 10-2 ~ 10-3 BER
0 5 10 15 20 2510-5
10-4
10-3
10-2
10-1
100
Modulation = 64QAM No. of Rx Ant = 1 = 0.7
U
ncod
ed B
ER
Eb/No
Alamouti case Profile A Profile B Profile C Profile DNo diversity case Profile A Profile B Profile C Profile D
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 101
doc.: IEEE 802.22-06/0005r5
Submission
Figure. BER performance vs. degree of correlation in 802.22 environments (Profile A, QPSK)
Performance Evaluation : STBC (4)
0 5 10 15 20 2510-5
10-4
10-3
10-2
10-1
100
Modulation = QPSK No. of Rx Ant = 1
Un
code
d B
ER
Eb/No
No diversity caseAlamoti case(Profile A) Correlation = 0.0 Correlation = 0.4 Correlation = 0.7 Correlation = 0.9
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 102
doc.: IEEE 802.22-06/0005r5
Submission
Degree of Correlation vs. Antenna Separation
Figure. Degree of correlation vs. antenna separation for various angular spreads (Laplacian model, zero nominal azimuth angle)
0 2 4 6 8 10 12 14 16 18 200.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
4o
2o
1o
0.5o
De
gre
e o
f Co
rre
latio
n
Antenna Separation (wavelength)
0.3o
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 103
doc.: IEEE 802.22-06/0005r5
Submission
FDFR
• The combination of pre-coder and the delay elements makes the error matrices full rank. FD.
• The loss by the tail edges becomes negligible as the block size increases.
• The interference from the previous vectors are subtracted while that from the later vectors are suppressed. The symbols within a vector are jointly decoded via ML, sphere decoder or any types of linear decoder.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 104
doc.: IEEE 802.22-06/0005r5
Submission
Presentation Outline
• PHY Proposal
• Updates to the MAC Proposal
• Conclusions
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 105
doc.: IEEE 802.22-06/0005r5
Submission
Disclaimer
• The following set of slides are restricted to describe only the updates to the MAC proposal described in documents 22-06-0003-01-0000 and 22-06-0005-01-0000 (presented in January/2006)
• The following updates together with document 22-06-0003-03-0000 represent the entire joint ETRI-France Telecom-I2R-Motorola-Philips-Samsung-Thomson MAC proposal
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 106
doc.: IEEE 802.22-06/0005r5
Submission
MAC Presentation Outline
• MAC Protocol– MAC layer data communication
• Support for Adaptive Antenna System (AAS)• Explicit outband signalling for hidden incumbent detection• Channel switch procedure
– Coexistence• Opportunistic in-band sensing• Credit tokens based rental protocol for inter-BS dynamic resource sharing• Enhanced measurement and channel management capabilities
– Clarifications• Frequency hopping• Support for Single Channel CPEs• Quiet period management for sensing
• Performance Evaluation– Synchronization of overlapping BSs– CBP
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 107
doc.: IEEE 802.22-06/0005r5
Submission
MAC Presentation Outline
• MAC Protocol– MAC layer data communication
• Support for Adaptive Antenna System (AAS)• Explicit outband signalling for hidden incumbent detection• Channel switch procedure
– Coexistence• Opportunistic in-band sensing• Credit tokens based rental protocol for inter-BS dynamic resource sharing• Enhanced measurement and channel management capabilities
– Clarifications• Frequency hopping• Support for Single Channel CPEs• Quiet period management for sensing
• Performance Evaluation– Synchronization of overlapping BSs– CBP
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 108
doc.: IEEE 802.22-06/0005r5
Submission
MAC Highlights
• Some aspects of MAC have been inspired by the 802.16 MAC– E.g., Frame format and QoS model
• However, major enhancements have been made– A new superframe structure for better coexistence and self-coexistence,
synchronization, Part 74 beacon support, support for bonding, etc.– Support for multiple channel operation (contiguous or not)– Enhanced support for Adaptive Antenna System– Coexistence with both incumbents and itself (self-coexistence);
• Incumbent user avoidance and Spectrum measurements (incumbents and itself)• Channel classification and Management• Dynamic resource sharing, Coexistence Beacon Protocol (CBP), and Etiquette• Synchronization of overlapping BSs and quiet periods• Two-stage fast and fine sensing mechanism and opportunistic sensing• Embedded wireless microphone beacon mechanism• Clustering support
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 109
doc.: IEEE 802.22-06/0005r5
Submission
Support for Adaptive Antenna System (AAS)
• Optional mode
• MAC takes advantage of the increased capacity and range offered by AAS– Similar to 802.16e
• Frame structure simultaneously support AAS and non-AAS traffic
frame n-1 frame n frame n+1 ...Time
...
MAC Slot Number
Regula
rP
ream
ble
FCH
DS
-MA
PU
S-M
AP
Self-
coexi
stence
Ranging
UCS Notification
Burst CPE #3
Burst CPE #2
Burst CPE #1
AASDS Zone
Burst CPE #1
Burst CPE #2
Burst CPE #4
Burst CPE #5
Burst CPE #3
Burst CPE #4
Self-
coexi
stence
Burst CPE #6
Burst CPE #7
Burst CPE #8
TTG
k k+1 k+3 k+5 k+7 k+9 k+11 k+13 k+15 k+17 k+20 k+23 k+26 k+29
TV Channel N
TV Channel N+1
DS US
Logic
al M
AC
Channel N
um
ber
s
s+1
s+2
s+L
BW Request
RTG
AA
SP
ream
ble
AASUS Zone
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 110
doc.: IEEE 802.22-06/0005r5
Submission
Support for Adaptive Antenna System (AAS)
• For AAS downlink synchronization, a CPE utilizes the broadcast preamble
• For network entry and initialization, two options are possible:– CPE receives enough energy from the broadcast channel that
allows it to decode control information (e.g., UCD/DCD and maps)• Hence, proceeds with network entry and initialization
– Otherwise, BS shall dedicate a fixed and pre-defined portion of the superframe structure as initial ranging contention slots• Sufficient slots are used by the CPE as to allow the BS enough time to
beamform towards the CPE• CPE shall wait for transmission from BS before retry• Network entry and initialization proceeds after that
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 111
doc.: IEEE 802.22-06/0005r5
Submission
Support for Adaptive Antenna System (AAS)
Superframe n-1 Superframe n Superframe n+1 ...Time
...
Preamble SCH frame 0 frame 1 frame m...
Channelt-1
Channelt
Channel t+1
Time
Preamble SCH
Preamble SCH
Fre
qu
ency
Preamble SCHFrame
0Frame
1Frame
m... ...
AW
AW
AW
AW Preamble SCH
Preamble SCH
Preamble SCHFrame
0Frame
1Frame
m...
AW
AW
AW
Alert-Window (AW)
• Contention slots for initial ranging• Used by AAS CPEs and by single channel CPEs
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 112
doc.: IEEE 802.22-06/0005r5
Submission
Support for Adaptive Antenna System (AAS)
• Channel state information can be done in two ways:– Reciprocity: Assumes the upstream channel state estimation as the
downstream channel state– Feedback: CPE explicitly transmits the estimated channel to the
BS
• Two channel feedback options are available:– New MAC control messages (namely, AAS-CFB-REQ and AAS-
CFB-RSP) have been defined– Piggybacked together with the existing measurement reports used
for incumbents and other 802.22 systems
• Bandwidth request, incumbent notifications, measurement reports, etc.:– Can be done using either the broadcast allocations or by polling
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 113
doc.: IEEE 802.22-06/0005r5
Submission
Hidden Incumbent Systems
• A WRAN System is on service in channel x.– CR BS sensed some channels and it recognized channel x was available, or BS just
started the service based on its database information.
• Some CPEs inside the incumbent system radio area may not be able to decode the CR BS signal because of strong interference.
– So, the CPEs cannot report the existence of the incumbent system and current status to the BS.
– BS cannot recognize this situation because of no information.
– Also, some incumbent users have experienced interference from the WRAN system.
Ch x
CPE
Ch x
Incumbent System
CR SystemNot overlapped CR CPE
Overlapped CR CPE(cannot decode CR Signaland cannot report anything)
Incumbent user
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 114
doc.: IEEE 802.22-06/0005r5
Submission
• Hidden incumbent case occurs– When a BS starts the service,– The BS changes the service channel
• Candidate channel broadcasting by BS and sensing reports for the candidate bands by CPEs can reduce the possibility of hidden incumbent system.
• But, BS may change its service channel without notification.
• Problem– CPEs inside the overlapped area are aware of the strong interference by incumbent
system.– How to report it to BS?
• Implicit hidden incumbent case detection– A BS periodically sends sensing request and all CPEs respond.– If a BS did not receive sensing responses from some CPEs, then sends again.– After some trials, if still some CPEs don’t respond, BS notices hidden incumbent
system appearance and changes the channel.– Still there remains some problems some CPEs power off ( Confuses BS as if hidden incumbent case occurs) CPEs inside the overlapped area just turn on, hence the BS doesn’t know the
existence of CPEs.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 115
doc.: IEEE 802.22-06/0005r5
Submission
Explicit OutBand Signaling for Hidden Incumbent Case Detection
• Hidden Incumbent System Case Method– BS periodically broadcasts the information on current channel in
some of other unoccupied channels (e.g. candidate channels).• Out-band signal: control signal on the band other than current band.• This broadcasting signal follows the same PHY and MAC frame
architecture (not to necessitate additional protocol or PHY module).
– CPEs that are not able to decode the BS’s current service channel try to sense other channels to locate the BS signal.
– If CPEs receive the explicit out-band broadcast signal,• It recognizes the current service channel id.• If the current channel is already sensed and is found to be not
decodable, then the CPE sends a report to the BS using the upstream in out-band.
– After noticing the existence of the hidden incumbent,• BS changes its service channel to other available band.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 116
doc.: IEEE 802.22-06/0005r5
Submission
Ch A
Time
channelCh C
Ch B
Explicit outband signaling period
CPE that cannot decode the current service channel will try to sense other channels
The CPE finally receives at least one of the periodic outband broadcast signals
Frequency
Ch A Ch B Ch C Ch D Ch E Ch F Ch X Ch Y
Not available
Not available
CurrentServiceChannel
BS
OutbandSignal
broadcast
OutbandSignal
broadcast
OutbandSignal
broadcast
OutbandSignal
broadcast OutbandSignal
broadcast
Frequency
Ch A Ch B Ch C Ch D Ch E Ch F Ch X
Not available
Not available
CPENot
available
Ch Y
OutbandSignal
broadcastReport
service signal
OutbandSignal
broadcast
It can be decided by incumbent system detection time requirement.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 117
doc.: IEEE 802.22-06/0005r5
Submission
• Explicit out-band broadcast signal
– Follow the usual PHY and MAC frame architecture like in the service channel
– In SCH: need a flag to differentiate
• Regular service MAC frame (in service channel)
• Out-band broadcast signal MAC frame (for broadcasting channel)
– In DS-Bust: include service channel information
• Service channel numbers, candidate channel numbers, …
• Hidden incumbent case report
– When a CPE receives a out-band signal and if the current service channel is not decodable by the CPE, then
– Sends “Hidden incumbent report” to BS using the broadcasting US-Burst
FCH
US-MAP
DS - Burst DS-
MAP
US- Burst
SCH
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 118
doc.: IEEE 802.22-06/0005r5
Submission
• Hidden Incumbent System Report– CPE report can be either of
• “the current service channel x is not decodable”• “the current service channel x is used by a incumbent system”
– If the CPE can recognize incumbent signal.– CPE report can also include sensing result for some other channels.
• US resource (data-burst) allocation for “hidden incumbent report” report.– BS may allocate explicit resource to each CPE after CPE initialization procedure –
overhead– BS may list up slotted US busts for unknown CPEs, which possibly reply their
reports using one of the slotted busts. Slotted US burst size can be determined in accordance with the maximum hidden incumbent report size .
• CPEs that need to send “hidden incumbent report” contend each other• Random back-off to send a message.
• Some overheads necessary in BS to broadcast out-band signals in different channels.
• CPEs do not need any change on their implementation.• Implicit method can supplement the explicit method.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 119
doc.: IEEE 802.22-06/0005r5
Submission
Channel Switch Procedure
• WRAN system build a candidate channel list using distributed sensing.• When incumbent users and other WRAN system are detected in the current
operating channel, – The BS selects a channel CHselect from the candidate channel list, either randomly or based on
some algorithms.– Randomly selects a wait time twait from a time window [ Tmin, Tmax ]– Start a wait timer with Twait as the expiration time– Advertises the channel selection using backhaul channel or WRAN air interface before
jumping to CHselect.
• Meanwhile the WRAN system sense CHselect for incumbent signals and other WRAN systems
– If the channel CHselect is still idle/available, it jumps to CHselect when the wait timer expires. – If incumbent signals or other WRAN systems exist in CHselect , it goes back to the beginning
to select another channel from the candidate channel list or its previously operated channel if occupied by incumbent users
• If collision occurs after channel switch, it increase tmax and goes back to the beginning to select another channel from the candidate channel list or its previously operated channel if not occupied by incumbent users
– Otherwise, it decrease Tmax and remove CHselect from the candidate channel list.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 120
doc.: IEEE 802.22-06/0005r5
Submission
Selects a channel CHselect from the candidate channel list
Start a wait timer with Twait as the expire time
Randomly selects a wait time Twait from a time window [ Tmin, Tmax ]
Advertise the channel selection CHselect
Sense channel CHselect
Channel CHselect idle?
Wait timer expire?
Switch to channel CHselect
Stop the wait timerAdd previously operating channel not occupied by
incumbents to the candidate channel list
Detect incumbent users and other WRAN system on the current operating channel
Stop
Increase Tmax
no
yes
Incumbent users and other WRAN system on Channel CHselect?
yes
yes
no
Remove CHselect from the candidate channel list and reduce Tmax
no
Remove CHselect from the candidate
channel list
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 121
doc.: IEEE 802.22-06/0005r5
Submission
MAC Presentation Outline
• MAC Protocol– MAC layer data communication
• Support for Adaptive Antenna System (AAS)• Explicit outband signalling for hidden incumbent detection• Channel switch procedure
– Coexistence• Opportunistic in-band sensing• Credit tokens based rental protocol for inter-BS dynamic resource sharing• Enhanced measurement and channel management capabilities
– Clarifications• Frequency hopping• Support for Single Channel CPEs• Quiet period management for sensing
• Performance Evaluation– Synchronization of overlapping BSs– CBP
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 122
doc.: IEEE 802.22-06/0005r5
Submission
The Opportunistic In-band Sensing Scheme
• Applicable for those cases where the traffic is low, and so sensing can take place within a frame– For these cases, the opportunistic in-band sensing can have
performance benefits such as reducing detection time and improving detection accuracy
• This scheme may be able to run in parallel with the out-of-band sensing algorithm:– However, whenever there is contention between the opportunistic
in-band sensing and out-of-band sensing, out-of-band sensing shall take precedence
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 123
doc.: IEEE 802.22-06/0005r5
Submission
The Opportunistic In-band Sensing Scheme (cont.)
• The main idea is to use common “sensing-eligible” frames to do in-band sensing
• A “sensing-eligible” frame is:– A frame with no traffic, i.e. no US or DS traffic
– A frame at which the backlogged traffic (both US and DS) is less than the remaining capacity in the current superframe and no sensing frame has been allocated in the superframe
– The last frame of the superframe and no sensing frame has been allocated in the superframe
• A “sensing-eligible” frame is designated as a sensing frame if it is not marked for use for out-of-band sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 124
doc.: IEEE 802.22-06/0005r5
Submission
Start of a newframe
Current framehas traffic?
backloggedtraffic
< remainingcapacity?
Is this the lastframe?
Sensing frameallocated in
superframe?
Current frame isa sensing frame
no
yes
yes
no
yes
no
Current frame nota sensing frame
no
yes
The opportunistic in-band sensing scheme
The Opportunistic In-band Sensing Scheme (cont.)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 125
doc.: IEEE 802.22-06/0005r5
Submission
Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing
• Rental Protocol– Offeror
– Renter
• Problem: – How to deal access/usage contention issues when several renters compete
to access to the same offer at the same time ?
– How to schedule the competing renters in a fair fashion while maximizing the spectrum efficiency ?
• The proposed mechanism complements the existing proposal– It introduces a cooperative sharing negotiation protocol: credit tokens
based rental protocol between one offeror and several renters
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 126
doc.: IEEE 802.22-06/0005r5
Submission
Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing
(cont.)• Definition
– Radio channel: time*frequency.– BIN = time unit*frequency unit.– A radio channel = a number of BINs.– Credit Tokens (CT): « money like » unit.
• What can be shared/negotiated?– Number of BINs for a given time duration.– The starting time of the sharing.– The ending time of the sharing.
• Principles– Each offeror and renter BS is prior allocated with a given credit tokens budget.– A BIN is charged as a number of CT per time*frequency unit.– A radio channel can be shared by exchanging CT between offeror and renter.– The exchange is dynamic and supported through the CT transactions.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 127
doc.: IEEE 802.22-06/0005r5
Submission
Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing
(cont.)• Principles
– Transactions rely on the real time and dynamic usage of reserve price auctionning and bidding mechanisms (e.g. ascending bid auction) to solve contention issues between renters BSs:• Offeror = auctionner• Renter = bidder
– BSs do not manipulate money. CT is used for self coordination in a distributed fashion between BS (self gouvernance).
– Incentive for sharing and fairness support is achieved through CT awarding.
• The credit tokens usage at each BS is ruled by the radio etiquette.
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 128
doc.: IEEE 802.22-06/0005r5
Submission
Credit Tokens based Scheduling Cycle
Resou
rce U
sage p
hase
(10) BW Granting
(9) Transaction
(8) Final Bidding results/Pricing
(5) (n-1)th Bidding results
(6) Express new bidding (nth)
(7) nth Bidding results
Offeror BS Renter BS
nth iteration
(n >
1) of th
e dyn
amic cred
it tok
ens b
ased
auction
ing/b
idd
ing
ph
ase
Fin
al pricin
g an
d
Tran
saction
ph
ase
Cred
it token
s b
ased B
W
Gran
ting
ph
ase
First iteration
(n =
1) of th
e dyn
amic
credit tok
ens
based
auction
ing/b
idd
ing
ph
ase
Interest
expressin
g p
hase
(1) Awareness/Advertising
(3) Inform bidding phasing
(2) Express interest
(5) 1st Bidding results
(4) Express initial bidding
Offeror BS Renter BS
Ad
vertising p
hase
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 129
doc.: IEEE 802.22-06/0005r5
Submission
Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing
(cont.)• This credit tokens based rental protocol can be implemented:
– either over the air (MAC level)– or the backhaul (wired)
• For the over air implementation, the credit tokens based rental protocol rules the MAC frame structure sharing between renters and offerors
• Scalable for different resoure renting timescales– Different auctioning strategies can be applied depending on the time constraints for
the negotiation
• Credit token charging mechanisms (different auctioning strategies) can be dynamically tuned to the context through the radio etiquette
– Space time traffic intensity variations in each cell– Number of bidders– ...
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 130
doc.: IEEE 802.22-06/0005r5
Submission
Enhanced Measurement Capability
• Besides the detailed and on-channel report, a CPE can now send a Consolidated Spectrum Occupancy Report– A Consolidated Spectrum Occupancy Report conveys a summary
of the overall spectrum occupancy from the point of view of a CPE
• For a particular channel, the CPE reports its state as a 3 bit field:– Unmeasured
– Vacant
– Occupied (i.e., energy detected)
– Occupied by an Incumbent
– Occupied by 802.22
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 131
doc.: IEEE 802.22-06/0005r5
Submission
Enhanced Channel Management Capability
• Based on the measurement reports from CPEs, a BS can transmit a Channel Occupancy Update message to CPEs– Allows quicker recovery, more efficient measurements, etc.
• Similar to a CPE, for a particular channel the BS reports its state as a 3 bit field:– Unmeasured– Vacant– Occupied (i.e., energy detected)– Occupied by an Incumbent– Occupied by 802.22
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 132
doc.: IEEE 802.22-06/0005r5
Submission
MAC Presentation Outline
• MAC Protocol– MAC layer data communication
• Support for Adaptive Antenna System (AAS)• Explicit outband signalling for hidden incumbent detection• Channel switch procedure
– Coexistence• Opportunistic in-band sensing• Credit tokens based rental protocol for inter-BS dynamic resource sharing• Enhanced measurement and channel management capabilities
– Clarifications• Frequency hopping• Support for Single Channel CPEs• Quiet period management for sensing
• Performance Evaluation– Synchronization of overlapping BSs– CBP
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 133
doc.: IEEE 802.22-06/0005r5
Submission
Frequency Hopping
• Purpose– To dismiss any presumption that the proposed MAC does not allow
frequency hopping
• Treated as an optional implementation issue provided the technical hurdles can be overcome
• In order to avoid an in-band quiet period, a WRAN may hop to a Channel A provided:– The Channel A evaluation meets the Channel Availability Check Time as
specified in the FRD
– The Channel A is not occupied by any incumbent
– The Channel A is not occupied by any 802.22 network• Otherwise, it may be worse than sticking to your current channel
– Adjacent channels have also been checked for the presence of incumbents, as to adhere to the EIRP profile
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 134
doc.: IEEE 802.22-06/0005r5
Submission
Support for Single Channel CPE
• At this point, channel bonding (of up to 3 contiguous TV channels) is an optional feature– This implies that BSs and CPEs may have different capabilities
• What happens if a BS is in channel bonding mode when a single channel CPE attempts to joint the network?
• To support this feature, an Alert Window (AW) is added to the superframe structure– Used to notify the BS about incoming CPEs who cannot operate in
the same mode as the BS
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 135
doc.: IEEE 802.22-06/0005r5
Submission
Support for Single Channel CPE (cont.)
Superframe n-1 Superframe n Superframe n+1 ...Time
...
Preamble SCH frame 0 frame 1 frame m...
Unit Channelt-1
Unit Channelt
Unit Channelt+1
Time
Preamble SCH
Preamble SCH
Fre
qu
en
cy
Preamble SCHFrame
0Frame
1Frame
m... ...Frame
1Frame
0
AW
Frame2
Frame0
Frame2
Frame0
Frame2
Preamble SCH
Preamble SCH
Preamble SCH
AW
AW
AW
Alert-Window (AW)
• Contention slots for initial ranging• Used by AAS CPEs and by single channel CPEs
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 136
doc.: IEEE 802.22-06/0005r5
Submission
Quiet Period Management for Sensing
• Background– A potentially very large number of channels (up to N±15) have to
be periodically sensed for the presence of incumbents– At the same time, support to QoS traffic requires delays as low as
20ms (see FRD)
• Question– How is sensing done as to meet these requirements?
• Answer– Sensing is a two-stage process
• Stage 1: Fast sensing (e.g., energy detection)• Stage 2: Only if needed, perform fine sensing (feature detection)
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 137
doc.: IEEE 802.22-06/0005r5
Submission
Quiet Period Management for Sensing (cont.)
• Quiet period structure
• The fast sensing is performed in-band only– May or may not be scheduled by the BS (e.g., between two
consecutive MAC frames)– Upon BS request, a consolidated report on the fast sensing
outcome is sent by CPEs– BS then determines the need for the next fine sensing and how
much time is required
BS1
Fast sensing 802.22 Transmission
Channel Detection TimeFast sensing Fine sensing
Fine sensing
Time
Channel Detection TimeFast sensing Fine sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 138
doc.: IEEE 802.22-06/0005r5
Submission
Quiet Period Management for Sensing (cont.)
frame n-1 frame n frame n+1 ...Time
...
MAC Slot Number
Pre
am
ble
FCH
DS
-MA
PU
S-M
AP
Se
lf-co
exi
ste
nce
Ranging
UCS Notification
Burst CPE #4
Burst CPE #2
Burst CPE #1
Burst CPE #5
Burst CPE #3
Burst CPE #7
Burst CPE #1
Burst CPE #2
Burst CPE #4
Burst CPE #5
Burst CPE #3
Burst CPE #6
Burst CPE #8
Burst CPE #9
Se
lf-co
exi
ste
nce
Burst CPE #6
Burst CPE #7
Burst CPE #8
TTG
k k+1 k+3 k+5 k+7 k+9 k+11 k+13 k+15 k+17 k+20 k+23 k+26
TV Channel N
TV Channel N+1
DS US
Lo
gic
al M
AC
Ch
an
ne
l Nu
mb
er
s
s+1
s+2
s+L
BW Request
Sensing RTG
Fast Sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 139
doc.: IEEE 802.22-06/0005r5
Submission
Quiet Period Management for Sensing (cont.)
• Since quiet periods from overlapping 802.22 cells are synchronized, sensing is highly effective
BS1
BS2
Time
BS3
Fast sensing 802.22 TransmissionFine sensing
Channel Detection TimeFast sensing Fine sensing
Channel Detection TimeFast sensing Fine sensing
Channel Detection TimeFast sensing Fine sensing
Channel Detection TimeFast sensing Fine sensing
Channel Detection TimeFast sensing Fine sensing
Channel Detection TimeFast sensing Fine sensing
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 140
doc.: IEEE 802.22-06/0005r5
Submission
Quiet Period Management for Sensing (cont.)
• Given that the nature of incumbent appearance on a channel is sparse (e.g., new TV stations do not come on the air every hour):– The fast sensing stage will be enough most of the time
– Hence, the fine sensing stage will not need to be performed
– Even if the fine sensing stage is required to be performed, its duration will exactly fit how much is required to be measured
• Therefore, with this mechanism: – Not only will incumbents have their protection guaranteed
– The stringent QoS requirements specified in the FRD will be met
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 141
doc.: IEEE 802.22-06/0005r5
Submission
MAC Presentation Outline
• MAC Protocol– MAC layer data communication
• Support for Adaptive Antenna System (AAS)• Explicit outband signalling for hidden incumbent detection• Channel switch procedure
– Coexistence• Opportunistic in-band sensing• Credit tokens based rental protocol for inter-BS dynamic resource sharing• Enhanced measurement and channel management capabilities
– Clarifications• Frequency hopping• Support for Single Channel CPEs• Quiet period management for sensing
• Performance Evaluation– Synchronization of overlapping BSs– CBP
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 142
doc.: IEEE 802.22-06/0005r5
Submission
Performance Evaluation
• Two aspects of the proposal are further evaluated– Distributed synchronization of overlapping 802.22 cells
• Four (4) step-by-step scenarios
• Overall convergence time for tens of thousands of scenarios
– Additional CBP protocol evaluation, which assesses• Self-coexistence
• Distributed quiet period synchronization of overlapping 802.22 cells
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 143
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs
• For all simulations– Number besides a node is the superframe transmission time (STT)
– Red line between nodes means nodes in range and STT NOT aligned
– Blue line between nodes means nodes in range and STT aligned
– Units• Time is milliseconds
• Space is kilometers
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 144
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs:Scenario 1
• A total of 24 WRANs are considered
• BSs and CPEs have a radio range of 25 Km
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 145
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 146
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs:Scenario 2
• A total of 30 WRANs are considered
• All WRANs power up at the same time (worst case analysis)
• BSs and CPEs have a radio range of 20 Km
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 147
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 148
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs:Scenario 3
• A total of 10 WRANs are considered
• All WRANs power up at the same time (worst case analysis)– Random STT at startup
• BSs and CPEs have a radio range of 20 Km
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 149
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 150
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs:Scenario 4
• A total of 10 WRANs are considered
• All WRANs power up at the same time (worst case analysis)– Random STT at startup
• BSs and CPEs have a radio range of 20 Km
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 151
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 152
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 153
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 154
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 155
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 156
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 157
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 158
doc.: IEEE 802.22-06/0005r5
Submission
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 159
doc.: IEEE 802.22-06/0005r5
Submission
Synchronization of Overlapping WRANs:Overall Convergence Time
• Comprehensive evaluation of the synchronization mechanism– Used for self-
coexistence (e.g., CBP) as well as for quiet periods
• Results show the quick convergence and efficiency of the algorithm– A similar scheme is
used in the WiMedia UWB MAC
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 160
doc.: IEEE 802.22-06/0005r5
Submission
CBP/Synchronization
• Evaluate the self-coexistence mechanisms of the proposed MAC– Synchronization– CBP in every frame
• The number of overlapping 802.22 cells are progressively increased– Up to 4 cells are simulated– BSs and CPEs start at random
• Network is fully loaded and traffic is uniform
1 cell:
2 cells:
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 161
doc.: IEEE 802.22-06/0005r5
Submission
CBP/Synchronization (cont.)
3 cells:
4 cells:
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 162
doc.: IEEE 802.22-06/0005r5
Submission
CBP/Synchronization (cont.)
• Simple scheduler
• CBP together with Synchronization can provide significant performance improvements– Since CBP is under control of
the BS, it can be made adaptive
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 163
doc.: IEEE 802.22-06/0005r5
Submission
Presentation Outline
• PHY Proposal
• Updates to the MAC Proposal
• Conclusions
March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Slide 164
doc.: IEEE 802.22-06/0005r5
Submission
Conclusions
• Presented the PHY proposal and updates to the MAC proposal– The proposal contains numerous mechanisms to protect incumbents while
meeting the requirements set forth by the 802.22 WG
• PHY– Based on OFDMA– Flexible channel configurations– TV and Part 74 service detection and protection
• MAC– Coexistence is a key feature
• Incumbent protection• Self-coexistence
– CBP, dynamic resource sharing, channel bonding, etc.