Doc.: IEEE 802.22-06/0069r0 Submission ETRI, FT, Huawei, Ga Tech, I2R, Motorola, NextWave, Philips, Runcom, Samsung, ST Micro, Thomson May 2006 Slide 1.

May 2006

Slide 1

doc.: IEEE 802.22-06/0069r0

Submission ETRI, FT, Huawei, Ga Tech, I2R, Motorola, NextWave, Philips, Runcom, Samsung, ST Micro, Thomson

Draft PHY/MAC Specification for IEEE 802.22IEEE P802.22 Wireless RANs Date: 2006-05-15

Authors:

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]

Soo-Young Chang Huawei USA +1-916-278-6568 [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]

Wendong Hu STMicroelectronics USA +1-408-467-8410 [email protected]

Ramon Khalona NextWave USA +1-760-710-2063 [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 (I2R) Singapore +65-68748225 [email protected]

Eli Sofer Runcom Israel +972-544-997996 [email protected]

May 2006

Slide 2

doc.: IEEE 802.22-06/0069r0


Co-Author(s):


Paul Piggin Cygnus

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 [email protected]

Youngsik HurGeorgia Institute of

TechnologyUSA +1-404-385-6008 yshur @ece.gatech.edu

May 2006

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doc.: IEEE 802.22-06/0069r0


Co-Author(s):


Jianwei Zhang Huawei China 86-21-6864480824638 [email protected]

Linjun Lv Huawei China 86-755-28973119 [email protected]

Lai Qian Huawei China 86-755-28973118 [email protected]

Jianhuan Wen Huawei China 86-755-28973121 [email protected]

Vincent K. N. Lau HKUSTHong Kong

852-2358-7066 [email protected]

Roger S. Cheng HKUSTHong Kong


Ross D. Murch HKUSTHong Kong


Wai Ho Mow HKUSTHong Kong


Khaled Ben Letaief

HKUSTHong Kong


Edward K. S. Au HKUSTHong Kong


Peter W. C. Chan HKUSTHong Kong


Chee Wei Ang I2R Singapore +65-68748225 [email protected]

Anh Tuan Hoang I2R Singapore +65-68748225 [email protected]

Peng-Yong Kong 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]

Francois Chin I2R Singapore +65-68748225 [email protected]

Zander Zhongding Lei I2R Singapore +65-68748225 [email protected]

Wing Seng Leon I2R Singapore 65-6874-7581 [email protected]

May 2006

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doc.: IEEE 802.22-06/0069r0


Co-Author(s):


Yufei Blankenship Motorola USA [email protected]

Brian Classon Motorola USA [email protected]

Fred Vook Motorola USA [email protected]

Jeff Zhuang Motorola USA [email protected]

Kevin Baum Motorola USA [email protected]

Tim Thomas Motorola USA [email protected]

David Grandblaise Motorola France +33 1 69 35 25 82 [email protected]

Dagnachew Birru Philips USA +1-914-945-6401 [email protected]

Kiran Challapali Philips USA +1-914 945-6356 [email protected]

Vasanth Gaddam Philips USA +1-914-945-6424 [email protected]

Monisha Ghosh Philips USA +1-914-945-6415 [email protected]

Zion Hadad Runcom Israel +972544 560 655 [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]

Kihong KimSamsung Electro-

MechanicsKorea [email protected]

May 2006

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doc.: IEEE 802.22-06/0069r0


Co-Author(s):


Seongsoo Lee Samsung Electro-Mechanics Korea [email protected]

Jeong Suk Lee Samsung Electro-Mechanics Korea +82-31-210-3217 [email protected]

Chang Ho Lee Samsung Electro-Mechanics Korea +82-31-210-3217 [email protected]

Wangmyong Woo Samsung Electro-Mechanics Korea +82-31-210-3217 [email protected]

David Mazzarese Samsung Electronics Co. Ltd. Korea +82 10 3279 5210 [email protected]

Baowei Ji Samsung Telecom America USA +1-972-761-7167 [email protected]

Changhoi KooSamsung Telecom

AmericaUSA +1-972-761-7934 [email protected]

Yinong DingSamsung Telecom

AmericaUSA +1-972-761-7975 [email protected]

Liwen Chu STMicroelectronics USA 408-467-8436 [email protected]

Kyeongsoo Kim STMicroelectronics USA 408-451-8137 [email protected]

George Vlantis STMicroelectronics USA 408-451-8109 [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]

May 2006

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Protection of Incumbents

• First and foremost requirement is protection of incumbent services– Broadcast TV– Part 74 Subpart H Low Power Auxiliary Stations (i.e., wireless

microphones)

• Database and location techniques are not part of this interoperability standard

• Mechanisms for incumbent awareness and avoidance are built into the MAC and PHY– Distributed spectrum sensing– Quiet period and fast/fine sensing management– Measurements and clustering– Detection algorithms– Spectrum management

May 2006

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Protection of Incumbents

• Protection of incumbents is the overarching requirement and so deserves priority in the presentation

• However, since this protection is so inextricably woven into the system, the PHY and MAC have to be introduced as a setting for these mechanisms

• Therefore, discussion of this topic will be distributed throughout the presentation

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Presentation Outline

• System Overview

• PHY Overview

• MAC Overview

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• System Overview

• PHY Overview

• MAC Overview

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Public IP Network

Service Provider IP Network

HAAAA

SD

ACR ACR

WRANBS

CPE

집

집 집

집

WRAN Hierarchy

• AAA : Authentication, Authorization and Account Server • ACR : Access Control Router HA : Home Agent

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집

집

집

집집

집

집

집

집

집 집

집

집

WRANRepeater

TV TransmitterWRAN

Base Station

WirelessMIC

집

WirelessMIC

집

WRANBase Station

집

집

: CPE집

집

집

집

집

집

: WRAN Base Station

집

집

집

집

집

집

집

집

집

집

집

집

집

Typical ~33kmMax. 100km

집 집

집집 집

집

집

집

Deployment Scenario

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System Overview

• OFDMA both in uplink and downlink• 2K FFT mandatory• TDD mandatory, FDD optional• 10 msec frame duration • 16-frame superframe• QPSK, 16-QAM, and 64-QAM, transformed-QPSK • Rate 1/2 through rate 5/6 coding• 30 - 32 sub-channels per TV channel• Data rate range from 4.8Mbps to 72.6Mbps (with

optional channel bonding and channel aggregation)

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Parameters Specification Remark

Frequency range 54~862 MHz

Service coverage Typical range 33 km

Bandwidth • Mandatory: 6, 7, 8 MHz

Optional fractional use of TV channel and channel bonding up to 3 contiguous TV channels. Channel aggregation of discontiguous channels.

Data rate• Maximum: 72.6 Mbps• Minimum: 4.8 Mbps

Maximum of 23 Mbps for 6 MHz

Spectral Efficiency

• Maximum: 4.03 bits/s/Hz• Minimum: 0.81 bits/s/Hz

Single TV channel BW of 6 MHz

Modulation QPSK, 16QAM, 64QAM mandatory

Transmit power Default 4W EIRP

Multiple Access Adaptive OFDMA Partial bandwidth allocation

FFT Mode 2K mandatory 1K / 4K optional, 2K / 4K / 6K for channel bonding

Cyclic Prefix Mode 1/4, 1/8, 1/16, 1/32

Duplex TDD mandatory FDD supported

Network topology Point-to-Multipoint Network

System Parameters

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• System Overview

• PHY Overview

• MAC Overview

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FFT Mode for WRAN Systems

No. of Bonded Channels Basic FFT mode

1 2 3

1K 1K 2K NA

2K 2K 4K 6K

4K 4K NA NA

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Subcarrier Spacing and Symbol Duration (2K)

GI = TFFT/32 GI = TFFT/16 GI = TFFT/8 GI = TFFT/4

TSYM

= TFFT + TGI

(s)

6MHz 308.000 317.333 336.000 373.333

7MHz 264.000 272.000 288.000 320.000

8MHz 231.000 238.000 252.000 280.000

6 MHz based channels

(6, 12 and 18 MHz)


(7, 14 and 21 MHz)


(8, 16 and 24 MHz)

Inter-carrier spacing,

F (Hz) = 3348.214 = 3906.25 = 4464.286

FFT/IFFT period, TFFT (s) 298.666 256.000 224.000

7256

106 6

7256

107 6

7256

108 6

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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

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Fractional Bandwidth Usage

• If wireless microphones are in operation in TV channel, the WRAN systems must 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

Other CR user

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SubchannelizationSubcarrier Allocation

AdjacentSubcarrier Permutation


Uniformly DistributedSubcarrier permutationUniformly DistributedSubcarrier permutation

Scattered typeScattered typeBand typeBand type


DistributedSubcarrier permutation

• Each subchannel consists of a

group of adjacent subcarriers

• Bands in good state are selected

for data transmission

• Multiuser diversity

• Require more feedback

information than distributed

subcarrier allocation type

• Each subchannel consists of

distributed subcarriers within an

OFDM symbol

• Only the average CINR over all

subcarriers is required

• For users with high frequency

selectivity or far distant users

May 2006

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Nc = # of sub-

CH

Nd = # of data

carriers/sub-CH

Np = # of pilots/sub-

CH

Nd+Np # of used carriers

Remarks

ETRI 30 28

48

52

28

8

4

56 56*30 = 1680

Worst CH

Medium CH

Best CH

I2R 32 48 4 or 6 52 or 54 52*32=1664

or

54*32=1728

Philips 32 48 6

(would agree to 4)

54 54*32=1728

OFDMA Parameters: Status

Runcom has also proposed single channel parameters based on 802.16ePUSC (1680 used sc) and FUSC (1702 used sc)

May 2006

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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 k+29

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

RTG

Frame Structure

May 2006

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Frame Element Definitions

• Preamble – synchronization, channel estimation– Long training sequence and optional short training sequence

– There’s also an upstream burst preamble

• FCH – frame control header, info on size of DS- and US- MAP and channel descriptors (PHY characteristics)

• MAPs – resource scheduling info for user bursts

• Ranging – timing offset, power adjustment

• UCS – urgent coexistence situation, incumbent detection report

• BW Request – self-explanatory

• SSS - sliding self-coexistence slots – used by coexistence beacon to improve coexistence with neighbors

• BCH – burst control header for upstream – ID information

May 2006

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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


Framen


Framem

Framem-1

May 2006

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Superframe Element Definitions

• Preamble – synchronization, channel estimation– Two symbols long with 5 short and 2 long training sequences

• SCH – superframe control header – info on system type, channel, channel bonding, quiet periods (time to, duration of)

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Channel Coding

• Convolutional Coding (mandatory)– Rate ½, other rates by puncturing

– Constraint length 7

• Optional Advanced Codes– Duo-binary Convolutional Turbo Coding (DB-CTC)

• see 8.5.2.2

– Low-Density Parity Check Coding (LDPC) • see 8.5.2.3

– Shortened block turbo codes (SBTC) • see 8.5.2.4

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Sensing

• Proposed methods still remain to be evaluated and compared (Tiger Team)

• Several techniques were introduced at previous meetings and have been included in the PHY spec in section 8.8– Energy detection (full bandwidth or pilot)

– Multi-resolution spectrum sensing and Analog auto correlation

– PN511 or PN63 sequence detection

– Segment sync detector

– Cyclostationary feature detection

– Spectral correlation

– Optimal radiometer

• Primary waveforms are DTV and analog FM for wireless microphones– 802.22 TG1 beacon in MAC Section 6.21.1.7.x

– More on this later

May 2006

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Multiple Antenna Options

• The following options are under consideration (Sec. 8.10)– 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

– Virtual MIMO

• Final decisions on which ones are included will be based on performance and complexity

• Please also refer to Samsung contribution on EIRP analysis

• MAC already provides support for multiple antennas

May 2006

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• System Overview

• PHY Overview

• MAC Overview

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Reference Architecture(Channel Aggregation support)

Convergence Sublayer / Bridge (e.g., 802.1d)

MAC

PHY

...MAC

PHY

MAC

PHY

Spectrum Manager

Higher Layers: IP, ATM, 1394, etc.

PHY/MAC 1 PHY/MAC 2 PHY/MAC n

Spectrum Manager – facilitates use of non-contiguous channels (channel aggregation) – responsible for maintaining global view of target RF spectrum – assigns spectrum to MAC/PHY modules

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MAC View of Frame

frame n-1 frame n frame n+1 ...Time

...

DS PHY PDU

Preamble FCH DS burst 1 DS burst 2 DS burst x...

BcastMsgs

MACPDUs

MAC PDU 1 ... MAC PDU y Pad

MACHeader

MAC Payload CRC

DS subframe

Initializationslots

BW requestslots

US PHY PDU(CPE m)

US PHY PDU(CPE p)

...

US subframe

Preamble US burst

MAC PDU 1 ... MAC PDU k Pad

MACHeader

MAC Payload CRC

Sliding self-coexistence

slots

Can appear ineither DS or US

BCH

UCSNotification

Slots

PDU – protocol data unit

CRC – cyclic redundancy check

Header – PDU length, connection ID, encryption

May 2006

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MAC Frame Slotted Structure

frame n-1 frame n frame n+1

Adaptive

N slotsDownstream (and Upstream) Upstream

...Time

...

• Each frame is formed by an integral number of MAC slots– 1 MAC slot = 1 modulation symbol

• Boundary between upstream and downstream is adaptive to accommodate traffic asymmetry

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Network Entry and Initialization

• BS initialization…– Consult TV usage database and regional WRAN information

database to identify candidate channels– Perform sensing to confirm vacancy of channels– Establish operation on a vacant channel

• The CPE will…– Scan a previous list of candidate channels or all downstream

channels until it finds a valid downstream signal– After acquiring the SCH, sense on all relevant channels

surrounding operating channel– Obtain upstream and downstream parameters and perform initial

ranging

• See sections 6.15.1+

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Network Entry and Initialization

• The CPE needs to be sure that its communications will not cause harmful interference before it first transmits

• If a CPE inside of a protected contour can both detect the incumbent and synchronize to the co-channel BS, it will not associate with the BS

• However, if allowed it may send a short message to alert the BS to the presence of the incumbent

• See section 6.15

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Ranging

• Downstream management– If CPE CINR falls below the range required for the specified burst

profile, the CPE requests transition to a new burst profile

– See section 6.17.1

• Upstream management– Consists of two procedures:

• Initial ranging allows a CPE to join a network and acquire correct Tx parameters

• Periodic ranging allows the CPE to maintain upstream communications

– For periodic ranging, timers must be maintained for each channel in DFH operation

– The algorithm is described in section 6.17.2

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QoS

• The service model is similar to that specified in 802.16

• The primary purpose is to define transmission ordering and scheduling over the air interface

• Packets traversing the MAC interface are associated into a service flow as identified by the connection identifier (CID)

• A service flow is characterized by a set of parameters such as latency, jitter, and throughput assurances

• See section 6.20.x

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CH-1 MAP CH-3 MAP

time

Burst #1

Burst #3

Burst#2

Burst#5

Burst#4

Burst #6

DS

DS

Multi-CH Resource Allocation by CH Grouping:The size of both FA-1 MAP and FA-3 MAP can be reducedby using the Channel Grouping and Matching which is managed by SM (Spectrum Manager)

Channel Grouping and Matching

CHMatching

1

3

3

1’

3’

3’

CH Matching:To select (US and

DS) active set 1 for individual CPE

CPE 1

CPE 2

CPE 3

CH Matching

BSCH Grouping:

To select a group of CPE’s that are assigned

to the same channelCH-1MAP

Burst #1

Burst #3 Burst#2

Before Matching and Grouping

After Matching and Grouping

May 2006

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Dynamic Frequency Hopping• An optional feature when the number of vacant channels exceeds

the number of neighboring BSs

• Avoids inband quiet periods and interruptions to service by hopping to other vacant channels for operation while sensing is performed on the previously occupied channels and other channels

• Regular periodic channel maintenance is combined with DFH to minimize frequency switching latency

ChannelAvailability Check

<2s > 30 seconds

ChannelSet Up

Ch X

Channel Availability CheckCh Y

Channel Sensing

ChannelSet Up

Transmission& Channel

Maintenance

Channel Sensing

2 seconds

<2s

Channel Sensing

Ch Z Channel Availability CheckChannelSet Up

Channel Sensing

2 seconds

ChannelSensing

ChannelSensing

ChannelNon-occupancy

Time


Maintenance


Maintenance


Maintenance

…...

…...

<2s

Incumbent detected

2 seconds

May 2006

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Clean Sensing for DFH

Ch A

Ch B

Ch C

WRAN 1

WRAN 1

WRAN 1

WRAN 1

WRAN 1

WRAN 2WRAN 2

WRAN 2

WRAN 2

WRAN 2

Quiet Time Operation Periond

Ch D WRAN 1

WRAN 1

WRAN 2 WRAN 2 WRAN 1

WRAN 1WRAN 3

WRAN 3

WRAN 2

WRAN 2

WRAN 3

WRAN 3

WRAN 3

WRAN 3

WRAN 3

WRAN 3

• “N+1” Rule and Phase Shifting operation• 3 WRAN systems share 4 channels using DFH with clean sensing• See section 6.16.6 for more info

May 2006

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Incumbent Coexistence

• See section 6.21.1.4.x

• A comprehensive set of measurement and spectrum management commands is available

• Urgent coexistence situations can be reported through fields in the MAC header or through the UCS slots

• Sensing can be in-band (where quiet periods are required) and out-of-band (no quiet period required)

• In-band incumbent detection can take place during two phases– Quiet Periods; and

– Normal System Operation (e.g., opportunistic in-band sensing)

May 2006

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Incumbent Coexistence

• During Quiet Period Notification Phase– BS limits its downstream traffic so that ample time is allocated for CPEs

to report

– The BS indicates this to the CPEs through the MDP (measurement data preferred) field in the US-MAP

– CPEs with allocated BW that did not detect the incumbent can still use the US to transmit data

– Unresponsive CPEs are pursued to determine the source of the problem

– Only CPEs without US BW should use the UCS slots

• During Normal System Operation– CPEs with allocated BW send a BLM-REP (bulk measurement report)

with priority over other pending traffic

– If there’s insufficient BW, the CPE may use fields in the MAC header

– CPEs without allocated BW use UCS slots

May 2006

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Incumbent Detection Recovery

• To recover from an UCS, protocols are needed that enable the network to restore normal operation

• Backup channels are relied upon to quickly re-establish communications– Backup channels should be completely disjoint from the affected

channel to minimize the probability that the backup channel is also impaired

• In the event that no vacant channels remain, CPEs periodically monitor the status of a channel and inform the BS via the MAC header fields if the channel becomes available again

• See section 6.21.5.x

May 2006

Slide 42

doc.: IEEE 802.22-06/0069r0


Class B CPE for Part 74 Protection

• 802.22 TG1 is currently preparing to address enhanced protection mechanisms for hard-to-detect Part 74 low power auxiliary devices

• One possible method is to use a special class (class B) CPE as a beacon

• This CPE is initially tuned to the desired channel of Part 74 operation

• If no SCH are detected after a timeout, the channel is assumed unoccupied by WRANs– But it will continue to search for SCH during normal operation

• If SCH are detected, the QP info is used to build a QP map for all area WRANs to find QP opportunities

• Beacons are transmitted during the best QPs to maximize detection

• See section 6.21.1.7.x

May 2006

Slide 43

doc.: IEEE 802.22-06/0069r0


Hidden Incumbent Systems

• If a CPE cannot detect the BS due to strong interference from an incumbent, a “hidden incumbent” situation results – See section 6.16.4

• The BS can remedy this situation by periodically broadcasting out-band signaling on other vacant channels

• The CPE can respond on one of these channels and alert the BS to the hidden incumbent situation

• The BS responds to the alert by changing the operating channel

May 2006

Slide 44

doc.: IEEE 802.22-06/0069r0


Quiet Period Management for Sensing

• Sensing is a two-stage process– Stage 1: Fast sensing

– Stage 2: Only if needed, perform fine sensing

• The fast sensing is performed in-band only

• Based on the fast sensing outcome, BS determines the need for the next fine sensing and the required time

• The synchronization of overlapping BSs makes this scheme highly reliable

BS1

Fast sensing 802.22 Transmission

Channel Detection TimeFast sensing Fine sensing

Fine sensing

Time

Channel Detection TimeFast sensing Fine sensing

May 2006

Slide 45

doc.: IEEE 802.22-06/0069r0


Opportunistic In-band Sensing

• 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

May 2006

Slide 46

doc.: IEEE 802.22-06/0069r0


Distributed Quiet Period

• When multiple CPEs are operating on different aggregate channels, a hidden node can result if the CPEs only sense on their active channel

• Meanwhile the BS is broadcasting on all aggregated channels and interference to the incumbent results

May 2006

Slide 47

doc.: IEEE 802.22-06/0069r0


Distributed Quiet Period

• This situation can be remedied by distributing the quiet period

• Each channel is interrupted only once using DQP, while simultaneous QP would require 3x interruption in this example

• See section 6.16.7.1

May 2006

Slide 48

doc.: IEEE 802.22-06/0069r0


Self-Coexistence

• CMAC addresses self-coexistence amongst overlapping cells in two mandatory ways:– BS beacon (i.e., SCH) based– The Coexistence Beacon Protocol (CBP), which enables:

• Sharing in time and frequency• Dynamic resource offering and renting• Etiquette for channel assignment

• CBP follows a best effort model that:– Allows for direct BS-to-BS communication and communication via CPEs– The overlapping BSs synchronization mechanism makes it highly reliable– Can be implemented either over-the-air or via a backbone– Allow either one-way or two-way (i.e., negotiation) communication

• The CBP packet consists of a preamble (different than the superframe preamble) followed by the SCH with the CT (content type) field set and a CBP MAC PDU

May 2006

Slide 49

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Spectrum Contention

• Three options are described

• Spectrum Renting/Offering (Sec. 6.21.2.3.1)– Offerers share active and candidate channel sets with potential

renter

– Renter chooses from union of neighbor’s candidate channels and informs neighbors of choice and required rental time

• Credit Tokens (Sec. 6.21.2.3.5)– Neighboring BSs trying to share a resource negotiate rental fees

using psuedo-monetary credit tokens from an initial reserve

– By sharing resources, a BS can accumulate tokens to build up its reserve for future rentals (incentive for sharing)

May 2006

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Spectrum Contention• On-Demand Spectrum Contention (Sec. 6.21.2.3.4)• Negotiation based distributed spectrum sharing mechanism• Contention number exchange and comparison• Iteratively driven by internal or external demands for spectrum sharing • Allow different contention strategies and flexible strategy adaptation

Data Transmissions

Channel Evaluationand Selection

Sharing theselected channel

feasible?

No

Contention for owningthe selected channel

Selected channeloccupied by

802.22 systems?

Success ?

Transmissions withthe selected channel

Transmissions withoutthe selected channel

Yes

Yes

NoExternalDemand

InternalDemand

Yes

Initialization On-DemandSpectrum Contention

No

BS 2BS 3BS 1

Request/responses

via Control Channel

a

a

aSystem 3System 3System 3System 3System 3System 3System 3

System1System1System1System1System1System1System1

System2System2System2System2

Operation intervalOperation intervalOperation intervalOperation intervalOperation intervalOperation intervalOperation interval

Contention responseContention responseContention responseContention responseContention responseContention responseContention response

Contention requestContention requestContention requestContention requestContention requestContention requestContention request

c

b

Grace Period

May 2006

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Channel Switch Procedure

• WRAN system builds a candidate channel list using distributed sensing• When incumbent users and other WRAN systems 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 ]– Starts a wait timer with Twait as the expiration time– Advertises the channel selection using a backhaul channel or WRAN air interface before

jumping to CHselect

• Meanwhile the WRAN system senses 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 decreases Tmax and removes CHselect from the candidate channel list

May 2006

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MAC Adaptive Antenna System (AAS) Support

• Frame structure simultaneously supports AAS and non-AAS traffic

• CPE uses preamble for downstream sync

• Network entry and initialization– CPE decodes FCH if able

– Alternatively, BS can reserve portion of superframe as initial ranging/contention slots

• Channel state via reciprocity or feedback– MAC control messages

– Piggyback on existing measurement reports

May 2006

Slide 53

doc.: IEEE 802.22-06/0069r0


CPE Maximum Transmit Power Control (TPC)

• CPE can operate co- or adjacent channel provided it is outside of the protected contour

• On other channels surrounding a TV channel, a CPE must abide by TPC defined by an EIRP profile

• All active TV channels in the area within ±15 channels will contribute to the profile

• Flowcharts and examples are shown in 6.13.5.x

May 2006

Slide 54

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Pending Items

• Some items reviewed by the proposal team did not reach consensus (for a variety of reasons) in time for the May meeting but are still considered worthy of continued consideration

• These items need to be exposed to the WG so they are not “in the dark”

May 2006

Slide 55

doc.: IEEE 802.22-06/0069r0


Pending Items

• PHY– FT: OQAM/IOTA– I2R: Block spreading– Runcom: Macro-diversity

• MAC– FT: OFDMA subcarrier slot sensing– Huawei

• MAC management message• Guard interval for quiet period• Efficient control signaling for downlink allocated resources information broadcast• Effective and flexible structures for CPE CSIT collection

– I2R• Hidden incumbent problem• Adaptive TDD

– Samsung: Uninterrupted frame synchronization and channel estimation– STM

• Inter-BS communications• DFH community

Doc.: IEEE 802.22-06/0069r0 Submission ETRI, FT, Huawei, Ga Tech, I2R, Motorola, NextWave, Philips, Runcom, Samsung, ST Micro, Thomson May 2006 Slide 1.

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