13-1©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22 Wireless IEEE 802.22 Wireless Regional Area Networks Regional Area Networks ((WRANsWRANs))Raj JainProfessor of Computer Science and Engineering Washington University in Saint LouisSaint Louis, MO [email protected]/Video recordings of this lecture are available at:http://www.cse.wustl.edu/~jain/cse574-08/13-2©2008 Raj JainCSE574SWashington University in St. LouisOverviewOverview! IEEE 802.22: Key Features! IEEE 802.22 Superframe/Frame Structure! IEEE 802.22 Channel Management! Configuration/Security/Power Management! Co-Existence Beacon Protocol (CBP)! Geolocation/Database13-3©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22: Key FeaturesIEEE 802.22: Key Features! Uses 54 MHz-862 MHz TV Band! Designed to share spectrum when TV broadcast is off! 17 km to 30 km radius (100 km in good conditions)100 kmQPSK17 km64QAM30 km16 QAM13-4©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22: Key Features (Cont)IEEE 802.22: Key Features (Cont)! 1.5 Mbps Down, 384 kbps Up.! Coverage: 50% locations in the fringe areas and 99.9% time! 2 bps/Hz ⇒ 12 Mbps in 6 MHz channel ⇒ 255 users with 40:1 over-subscription13-5©2008 Raj JainCSE574SWashington University in St. LouisCharacteristics of Wireless StandardsCharacteristics of Wireless StandardsRANMANLANPANRangeData RateSpectrumStandard100km10km1000m100m802.15802.11802.16802.221Mbps11-200 Mbps1-70 Mbps1-10Mbps2.4 GHz2.4, 5.8 GHz2.5, 3.5 GHz54-862 MHz13-6©2008 Raj JainCSE574SWashington University in St. LouisSimilarities Between 802.16 and 802.22Similarities Between 802.16 and 802.22! Centralized allocation at BS! Service classes: UGS, rtPS, nrtPS, BE! QoS parameters, Peak/sustained rates, max latency, jitter! OFDMA, Slots, DS subframe, US subframe, BurstsDL/UL is called DS/US. SS is called CPE.! Connections, 12-bit connection ID (CID), Basic, Primary management, Secondary management connections! Ranging request/response! Contention: Ranging, BW request! MAC subheaders: BW request, fragmentation, grant management, packing, ARQ feedback, fast feedback13-7©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22 ConceptsIEEE 802.22 Concepts! Spectrum sensing: Check if TV/WRAN signal is present! In-band: Operating TV Channel N and the first adjacent channels (N+1 and N-1).! Out-of-band: Any TV channel that is not in-band! Geo-location: Latitude and longitude! Waypoint: Any WRAN device whose location is known. Used for geolocation.13-8©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22 Superframe StructureIEEE 802.22 Superframe Structure! Superframe: Group of 16 frames, with a superframe preamble and superframe control header (SCH).! First frame payload is reduced by two symbols to compensate for Superframe preamble and superframe control headerSuperframe n-1 Superframe n Superframe n+1Superframe PreambleFramePreambleSuperframeControl HeaderFramePreambleFrame 0 Frame 1 Frame 15160 ms13-9©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22 Frame StructureIEEE 802.22 Frame Structure! SCH indicates whether a frame or coexistence beacon follows it.! It also indicates the position and duration of quiet period for inter-frame sensing.! DS:US boundary is adaptive! DS bursts are vertical, US bursts are horizontal! Urgent Co-existence situation (UCS) notificationFrame PreambleDS-MAP FCHUS-MAPUCDDCDBurst 1Burst 2Burst nBurst 2Burst 1Burst 2Ranging/BWR/UCSSelf Coex Window13-10©2008 Raj JainCSE574SWashington University in St. LouisChannel Classifications and SelectionChannel Classifications and Selection! Available: Not occupied by TV transmitters" Disallowed: Local regulation" Operating: Used by this BS" Backup: In backup list of this BS" Candidate: For backup" Occupied: By other WRANs" Unclassified: Don’t know! Unavailable: Occupied by TV transmitters13-11©2008 Raj JainCSE574SWashington University in St. LouisIEEE 802.22 Channel ManagementIEEE 802.22 Channel Management! Channel Termination req/resp! Announced by BS if incumbent comes back! Channel Add req/resp to add TV channels to the BS channels! Channel Switch req/resp! Channel Quiet Request/resp (to perform measurement)! Channel Occupancy update! BS may get the list of incumbents from a database13-12©2008 Raj JainCSE574SWashington University in St. LouisMeasurements ManagementMeasurements Management! Bulk measurement request: Sent by BS to unicast/multicast/broadcast addressIncludes number of repetition and report frequency! Measurement response! Stop measurement request! Location configuration measurement request13-13©2008 Raj JainCSE574SWashington University in St. LouisConfiguration ManagementConfiguration Management! SW Upgrade TFTP server ! TFTP complete message13-14©2008 Raj JainCSE574SWashington University in St. LouisSecurity ManagementSecurity Management! Privacy key management req/reply reject/ack! PKM EAP start/transfer! PKM SA-TEK challenge13-15©2008 Raj JainCSE574SWashington University in St. LouisPower ManagementPower Management! 802.22 stations (BS or CPE) are not allowed to operate on active TV channel (N) or the adjacent channel (N+1)! Maximum EIRP is limited when operating on alternate channels (N+2 and beyond)13-16©2008 Raj JainCSE574SWashington University in St. LouisIDRPIDRP! Incumbent Detection Recovery Protocol ! BS transmits a channel switching req (CHS-REQ)! If a CPE misses the CHS-REQ, it times out if it does not hear from BS, CPE then moves to the next backup channel13-17©2008 Raj JainCSE574SWashington University in St. LouisCoCo--Existence Beacon Protocol (CBP)Existence Beacon Protocol (CBP)! For signaling to adjacent and overlapping WRAN cells and for geolocation! CBP bursts are transmitted by selected CPEs at the end of US subframe.! CPEs decode CBP packets from CPEs in cells operating on the same TV channel or adjacent channels.! 14 types of CBP packets including CPE beacons.! CPE beacons are transmitted by the CPEs and contain the TV channel #, backup channel #s, BS ID, CPE ID.! CBP packets are used for coexistence and Geolocation13-18©2008 Raj JainCSE574SWashington University in St. LouisSelfSelf--CoexistenceCoexistence! Two or more 802.22 networks in the same space/time/frequency1. Spectrum Etiquette: Do not hog the channels2. Interference Free scheduling: Do not allocate slots which interfere with neighboring cell's CPEs3. Dynamic Resource Renting and Offering: Less loaded BSs rent spectrum to more loaded
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