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doc.: IEEE 802.22-11/0130r1
Submission
IEEE 802.22 MAC/CC Overview
Nov. 2011
Gwangzeen Ko, ETRISlide 1
IEEE P802.22 Wireless RANs Date: 2011-11-02
Name Company Address Phone email Gwang-Zeen Ko ETRI Korea +82-42-860-4862 [email protected]
Byung Jang Jeong ETRI Korea +82-42-860-6765 [email protected]
Sung-Hyun Hwang ETRI Korea +82-42-860-1133 [email protected]
Jung-Sun Um ETRI Korea +82-42-860-4844 [email protected]
Antony Franklin ETRI Korea +82-42-860-0752 [email protected]
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 that the draft publication will be approved for publication. Please notify the Chair Apurva Mody <[email protected]> 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].
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 2
Abstract
This contribution summarizes the MAC and Cognitive Capability (CC) features in the IEEE 802.22-2011 Standard.
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 3
Contents• 802.22 MAC Features
– Introduction – Super-frame/Frame Structure– CBP summary and Coexistence schemes
• Dynamic QP Scheduling• Self-Coexistence Schemes
• Cognitive Capabilities in 802.22– Spectrum Manager– Channel Classification– Spectrum Sensing– Geo-location– DB Access
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 4
MAC Introduction (1)• Some aspects of IEEE 802.22-2011 MAC have been inspired from
the IEEE 802.16 MAC standard• Combination of polling, contention and unsolicited bandwidth
grants mechanisms• Support of Unicast/Multicast/Broadcast for both management and
data• Connection-oriented MAC
– Connection identifier (CID) is a key component• IEEE 802.22-2011 CID can be constructed from Station ID (SID) and Flow
Identifier (FID) [1]. This new CID definition can reduce overhead and storage requirements [2].
– Defines a mapping between peer processes– Defines a service flow (QoS provisioning)
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 5
MAC Introduction (2)
• However, major enhancements have been made– Support of Cognitive functionality
• Dynamic and adaptive scheduling of quiet periods• Various incumbent user detection and notification methods
– Coexistence with both incumbents and other 802.22 systems (self-coexistence)
• Measurements (incumbents and 802.22 operation)• Spectrum management (time, frequency and power)• The Coexistence Beacon Protocol (CBP)• The Incumbent Detection Recovery Protocol (IDRP)• Wireless microphone beacon mechanism (IEEE 802.22.1)
– Self-coexistence mechanisms• Spectrum Etiquette• On-demand Frame Contention
doc.: IEEE 802.22-11/0130r1
Submission
Superframe n-1 Superframe n Superframe n+1 ......
frame 0
Superframe Preamble SCH
frame Preamble
frame 1
Superframe Preamble
SCHframe Preamble
frame 15
frame Preamble
WRAN 0
WRAN 1
......
......
160 ms
10 ms
Time
frame n-1 frame n frame n+1 ...Time
...
FramePreamble FCH DS burst 1 DS burst 2 DS burst x...
UDCOptionalBroadcastMAC PDU
MAC PDU 1 ... MAC PDU y Pad
MAC Header MAC Payload CRC
Ranging slots
BW request slots
US Burst (CPE m)
US PHY PDU (CPE p)
...
MAC PDU 1 ... MAC PDU k Pad
MAC Header MAC Payload CRC
UCS Notification
Slots
DS subframe
US-MAPDS-MAP DCD
US subframe
TTGSelf Coexistence
Window RTG
Nov. 2011
Gwangzeen Ko, ETRISlide 6
IEEE 802.22 Frame Structure(Logical View)
Super frame Structure
Frame Structure
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 7
IEEE 802.22 Frame Structure(Physical View)
DS sub-frame TTG
RTG
US sub-frame(smallest US burst portion on a given subchannel= 7 symbols)
26 to 42 symbols corresponding to bandwidths from 6 MHz to 8 MHz and cyclic prefixes from 1/4 to 1/32Fr
ame
Prea
mbl
e
FCH
DS-
MA
P
Burs
t 1DCD
Burs
t 2 ti
me
buff
er
tim
e bu
ffer
Self
-coe
xist
ence
win
dow
(4 o
r 5
sym
bols
whe
n sc
hedu
led)
Burst 1
60 s
ubch
anne
ls
Burst 2
Burst 3more than 7 OFDMA symbols
Burst
Burst n
Burst
Burs
t m
Ranging/BW request/UCS notification
Burst
Burst
Bursts
Burs
ts
frame n-1 frame n frame n+1... Time...
10 ms
US-
MA
P
US-
MA
PU
CD
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 8
Concept of 802.22 Frame Operation
The allocation of burst could be based on distance of CPE
from BS in order to compensate the delay
of arrival
Contention for all CBP transmitters
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Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 9
SCH and CBP Features
• The Super-frame Control Header (SCH)– Provides the control information for a WRAN cell– Support the intra-frame and inter-frame quiet periods management mechanisms
for sensing– Support coexistence with incumbents and other WRAN cells (self coexistence)
• An SCH can include various CBP (Coexistence Beacon Protocol) IEs– Backup channel information IE– Frame Contention information IE– Terrestrial Geo-location information IE– Signature IE, Certificate IEs (CBP frame security)
• Using SCH, WRAN BS can intelligently manage the operation of its associated CPEs
• Also, using CBP (Extended version of SCH), WRAN BS can intelligently manage the operation of neighboring WRAN cell under co-existence situation
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 10
CBP Summary• CBP is used to communicate the operating parameters from one
WRAN cell to another WRAN cell• CBP packet is transmitted using SCW which contains the SCH of
its own WRAN cell• CBP is fully controllable by the BS that decides who sends/listens
and when to send/listen for CBP packets (Refer [3])– The source of a CBP packet can be either a BS or a CPE
• CBP packets carry only control information (no data)
Structure of a CBP packet
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 11
Dynamic Quiet Period Scheduling
Intra-Frame QP scheduling(Some part of super-frame)
QP < 1Frame
Intra-Frame QP scheduling(Some part of super-frames)
QP = 1 Frame
Inter-Frame QP scheduling(whole super-frame except SCH)
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 12
Self-Coexistence Mechanism (1)• Self-Coexistence: Co-existence among WRAN Systems [4]
(Exchange of information between BSs through CPEs using the self-coexistence window)
Coexistence beacon protocol
On-
dem
and
fram
eco
nten
tion
Spec
trum
etiq
uette
Orthogonal channel selection for operating channel and first
backup channel
Frame allocation signalledby the super-frame control
header (SCH)
MAC self-coexistence schemes PHY coexistence mechanisms
Enough channels available
Two or more cells need to coexist on the same channel
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 13
Self-Coexistence Mechanism (2)• Spectrum Etiquette [4]
• Orthogonal channel assignment scheme between adjacent cells– different operating channel for overlapping or adjacent cells– different first backup channel
1, 2, 7 3, 4, 2, 6, 7
5, 6, 2, 7, 84, 8, 2, 6, 7
3, 7, 2, 5, 8
6, 4, 2, 5, 7 8, 5, 2, 4, 7
7, 5 3, 4, 6
5, 6, 2, 84, 8, 2, 6
3, 2, 5, 8
6, 4, 2, 5 8, 5, 2, 4
1 2
Requires that information on operating, backup and candidate channelsof each cell is shared amongst WRAN cells: exchanged by CBP packets [5]
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 14
Self-Coexistence Mechanism (3)• On-demand Frame Contention
• Two or more cells need to co-exist on the same channel
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 15
Cognitive Capability
• Collection of Spectrum Information– Geo-location information (A)– TVWS Database (B)– CPE Spectrum Sensor (C)– BS Spectrum Sensor (D)
• Cognitive Engine (Decision Maker)– Spectrum Manager (BS)– Spectrum Automation (CPE)
• Configurable Communication System – 802.22 PHY– 802.22 MAC
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 16
Summary of Spectrum Manager [4]
Spectrum Manager
Policies
Incumbent Database Service
IncumbentDatabase
Spectrum SensingRF sensing performance
0.1%
1.0%
10.0%
100.0%
-26 -24 -22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2SNR (dB)
Prob
abilit
y of m
isdete
ction
(Pmd
)
Energy - 1dB Pfa=10% 5 ms
Energy - 0.5dB Pfa=10% 5 ms
Energy - 0dB Pfa=10% 5ms
Thomson-Segment Pfa=10% 4 ms
I2R Pfa=0.1% 4ms
I2R Pfa= 1% 4ms
I2R Pfa=10% 4 ms
Qualcomm Field Pfa=10% 24 ms
Qualcom Field Pfa=1% 24 ms
Thomson Field Pfa=10% 24 ms
Thomson Field Pfa=1% 24ms
Channel Set Management Subscriber Station Registration and Tracking
Self Co-existenceGeo-location
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 17
SM Channel Classification [5]Two step channel decision
External to IEEE 802.22 System
Internal to IEEE 802.22 System
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 18
Spectrum Sensing[6]
• IEEE 802.22 supports spectrum sensing capability by using SSA and SSF• Spectrum Sensing Automation (SSA, sensing manager)
– All the IEEE 802.22 devices (BS and CPEs) shall also have an entity called the Spectrum Sensing Automaton (SSA). The SSA interfaces to the Spectrum Sensing Function (SSF) and executes the commands from the SM to enable spectrum sensing
• Spectrum Sensing Function (SSF, sensor)– Spectrum sensing is the process of observing the RF spectrum of a television
channel to determine its occupancy (by either incumbents or other WRANs).– The base station and all CPEs shall implement the Spectrum Sensing Function
(SSF)– The SSF shall be driven by the SSA. The SSF shall observe the RF spectrum of
a television channel and shall report the results of that observation to the SM (at the BS) via its associated SSA
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 19
Spectrum Sensing [6]
Spectrum Sensing Automation state machine Input/Output of the Spectrum Sensing Function
doc.: IEEE 802.22-11/0130r1
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Nov. 2011
Gwangzeen Ko, ETRISlide 20
Geo-Location• Satellite based geo-location [7]
– Requires GPS antenna at each device– NMEA 0183 data string used to represent geo-location– Poor accuracy in Northern hemispheres
• Terrestrial based geo-location [4]– Besides satellite-based geo-location, the 802.22 standard includes terrestrial
geo-location using inherent capabilities of the OFDM based modulation and the coexistence beacon protocol bursts transmitted and received among CPEs
– Propagation time measured between BS and its CPEs and among CPEs of the same cell using Fine Time Difference of Arrival: TDOA
BS Vernier-1
Vernier-2
CPE1
Downstream
Upstream
Vernier-3CPE
2
CBP burst
Vernier-1
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 21
DB Access• WRAN DB access [6]
– 802.22 WG defined DB access structure– Interfaces are defined between DB and BS
• Defined number of primitives for DB access
– M-DB-AVAILABLE-REQUEST– M-DEVICE-ENLISTMENT-REQUEST– M-DB-AVAILABLE-CHANNEL-
REQUEST– M-DB-AVAILABLE-CHANNEL-
INDICATION– M-DB-DELIST-REQUEST– Etc.
Structure of the IEEE 802.22 WRANaccess to the database service
doc.: IEEE 802.22-11/0130r1
Submission
Nov. 2011
Gwangzeen Ko, ETRISlide 22
References
[1] “Additional text to implement new connection identifier management approach”, 22-10-0137-02-0000, Aug. 2010.
[2] “New connection identifier approach”, 22-09-0112-05-0000, Jul. 2010.[3] “Overview of CBP”, 22-07-0136-00-0000, Apr. 2007.[4] “802.22 Coexistence Aspects ”, 22-10-0121-02-0000, Sep. 2010.[5] “Channel Management in IEEE 802.22 WRAN Systems”, IEEE Communication Mag
azine, vol.48, No.9, Sep. 2010.[6] “IEEE P802.22-2011: Standard for Wireless Regional Area Networks Part 22: Cognit
ive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies and procedures for operation in the TV Bands”, Jul. 2011.
[7] “IEEE 802.22 Wireless Regional Area Networks”, 22-10-0073-03-0000, Jun. 2010.