Vehicle Positioning, Digital Maps and Integrated ServicesLecture 7 WAVE Protocols

OutlineWAVE IntroductionWAVE1609.1WAVE1609.2WAVE1609.3WAVE1609.4

IntroductionDSRC5.9GHz DSRCMACPHYIEEE802.11p.802.11pIEEE2003802.11aWAVE(Wireless Access in the Vehicular Environment)DSRC

IntroductionITSDSRC

Introduction: Bluetooth (BT), Ultra-wideband (UWB)

: 2G, 2.5G, 3G, 3.5G (cellular systems), GPS, WiMAX

: Microwave, Infrared, Dedicated Short Range Communications (DSRC), Wi-Fi

: Microwave, Infrared, DSRC

Introduction(microwave)(infrared)(radio frequency, e.g. DSRC)

Introduction(V2R, OBU-to-RSURSU-to-OBU)

(V2V, OBU-to-OBU)

DSRC

1050 m (line-of-sight) kbps

Wi-Fi WLAN: 10100 m ideal: a: 54Mbps11b: 11 Mbps11g: 54 Mbps DSRC WLAN: 3001000 m mobile: 327 Mbps

DSRC/WAVE

Vehicle to vehicle

Service channel

Service channel

Control channel

Intersection

DSRC/WAVE

*WMEUDP/TCPWSMPLLC WAVE MACWAVE PhysicalManagement planeData planeWAVE Protocol Stack ModelIPv61609.3MLMEPLMEMulti-channel operation1609.41609.3802.11p802.2Application1609.1Application Presentation SessionNetworkData LinkPhysicalTransportOSI Reference Model802.11SecurityServices1609.2

Noun interpret(1)Wireless access in vehicular environment (WAVE): IEEE

Onboard unit (OBU):WAVERSUOBU

Roadside unit (RSU):WAVEOBUs

Noun interpret(2)Provider Service Table (PST):WAVE devicechannel

Provider Service Context (PSC):PSID

Provider service identifier (PSID)

Noun interpret(3)WAVE management entity (WME):WAVE networking

WAVE short message (WSM):IPWAVE device

WAVE short message protocol (WSMP): WAVE shot message

Noun interpret(4)WAVE basic service set (WBSS)WAVESCHWBSSWAVEWAVECCH

WAVE routing advertisement (WRA):RSU

Noun interpret(5)WAVE service advertisement (WSA)WAVEWMEWAVE

WAVE service information element (WSIE)WAVEWAVE

System components and connectivity Two types of systems identified in the WAVE standards. The first type is a roadside unit (RSU). The second type is an onboard unit (OBU).

*IEEE 1609.1IEEE 1609.1 : resource manager IEEE 1609.1 WAVE DSRC WAVE (OBU) (RSU) WAVE

IEEE 1609.2IEEE 1609.2 : secure message formats to process secure messages of the DSRC/WAVE DSRC WAVE

WAVE

Scope & purposeDefine secure message formats, the processing of the secure messages within the DSRC/WAVE systemMethod for securing WAVE management messages and application messages excepting vehicle-originating safety messagesServices used to protect messages from attacks

WAVE systems overviewEntities in the systemProvidersUsersRoadSide Units (RSUs) WAVE devices operate only when stationarySupport information exchange with OBUsUsually be providersOn-Board Units (OBUs)WAVE devices operate in motionSupport information exchange with RSUs and other OBUsUsually be users (may be providers)Public Safety On-Board Units (PSOBUs)Certificate Authorities (CAs)Support security servicesAuthorize other entities via the issuance and revocation of certificates

WAVE systems overview

WAVE systems overview-Messages for WAVE radio stackWAVE Short Message (WSM) for broadcast applications over WSMP (network layer)UDP/IP stack for transactional applications (network layer)WAVE Service Announcement (WSA) for providers notifies users which the services are and what service channel(s) they are provided on (MAC layer)All generated by the WAVE Management Entity (WME)

WAVE systems overview Security servicesApplications over UDP use the secured message formats to protect application data (Encrypted Message)Application over WSMP use the secured message formats or the secured WSM types to protect application data (Signed Message)WME uses the secured WSIE type to preventing fake services (Signed Message)

Secured message format

Secured message format

Secured message format

Secured message format

Secured message format

Secured message format

Secured message format

Secured message examples

Secured message examples

Communication security overviewAttacksIntercept a messageAlter the messageReplay a messagePreventionConfidentiality encrypting the messageAuthenticity confirmation of origin of the messageIntegrity confirmation that the message has not been altered

Cryptographic servicesSymmetric algorithm (secret-key)Two entities share a secret-key and uses this key to encrypt/decrypt the message and provide authenticity and integrityOnly the party shares the key knows who generates the messageAES-CCM (authenticate-then-encrypt) adopted by this standard Asymmetric algorithm (public-key)Two keys: public key and private keyIn WAVE context, broadcast messages are signed and are not be encryptedTransactional messages are protected with asymmetric or symmetric algorithms

Cryptographic servicesHash functionsSHA-1 are adopted by this standardUse to generate identifiers to certificates and fragmented messagedFor efficiently operate the cryptographic algorithmAsymmetric algorithms are used to setup a secure-sessionSymmetric algorithms are then used to protect data

The construction and use of signed messages

Flow Chart

Issuer requests certificate from CA

CA response with corresponding certificate and CRL

WAVECertificateRequest

WAVECertificateResponse

Sender send signed message with certificate and signature

Receiver verifies the message by certificate and the signature

SecuredMessage(Signed Message)

Sender send encrypted message

Receiver decrypts the message by symmetric key

SecuredMessage(Encrypted Message)

Summary of IEEE 1609.2

AnonymityMechanism for providing anonymous authenticated broadcast messaged are not given in this standard at this timeThe current standard is focus on protecting message payloads and does not provide the protection for message headers

IEEE 1609.3IEEE 1609.3 : network services WAVE WAVE WAVE OSI IEEE 1609.3 IPv6 WAVE short message (WSM)

WAVE network services (1/3)IEEE 1609.3 WAVE

IEEE 1609.3 5.9GHz DSRC/WAVE

WAVE network services (2/3) WAVE Data Plane() UDP (TCP)IPv6 WAVE Short Message (WSM) Protocol (WSMP) WAVEIPv6WSMP

WAVE network services (3/3)Management Plane()(WAVE basic service set ,WBSS)IPv6

Communication protocols (1/2)Channel typesCCH (single control channel)shorthigh-priority application system control message SCH (multiple service channel)

Communication protocols (2/2)WAVE Short Message Protocol (WSMP)WAVE (CCH or SCH) PHY()WAVE Short Messages (WSMs)PSID

IPv6SCH

IEEE1069.3 Protocol Stack Modelnon-IP based

Datagram different in TCP/IP and WSM( Wave Short Message )

Logical Link Control (LLC) IPv6 type packets received from the lower layers with an Ethernet Type value of 0x86DD are delivered to the IPv6 protocol. WSM packets received from the lower layers with an Ethernet Type of 0x88DC are delivered to the WSM protocol. IPv6 packets for transmission shall have Ethernet Type set to 0x86DD. WSM packets for transmission shall have Ethernet Type set to 0x88DC

Service request summary table & graphalternatingimmediateextended

Service access point

WAVE Basic Service Set (WBSS)WBSSWAVEWBSS WBSS

WSMPWBSSSCHWSMsCCH

WAVE Communications ConceptsWBSSWBSSWSMsCCHWBSSWSMsIPv6SCHWBSS(persistent)(non-persistent)Internet accessDevice WBSS rolesWBSSrolePrioritiesWMEMAC

Operation without a WBSSWSMMACWSMPpower leveldata rateWSMWSMPCCHpacket passcommunication stackWSMPPSIDCCH

Operation with a WBSS (1/2)WBSS Persistent WBSSCCH

Non-Persistent WBSS

Operation with a WBSS (2/2)WAVE Service Information Element (WSIE)WAVEWSIEWAVE Service Advertisement (WSA)WSIEWBSSWMEWME-Application.request WMEMLME-WSA.request WBSS

WAVE Service Information Element (WSIE)Reference by IEEE 1609.3

Service usage examples(1/4)

Service usage examples(2/4)

Service usage examples(3/4)

Service usage examples(4/4)

Wave Service Advertisement format

WSM format

WAVE Element ID

IEEE 1609.4Discuss the WAVE multi-channel operationsMAC (Control Channel, CCH) (Service Channels, SCH) ()

General descriptionWAVE (OBU RSU) (CCH) (SCH)CCHWSMWAVESCHs(Physical layer, PHY) IEEE 802.11 IEEE 802.11p

Reference ModelWMEUDP/TCPWSMPLLCWAVE MAC with channel coordinationWAVE PhysicalManagement planeData planeIPv6MLMEPLMEApplicationFocus of enhancementsSpecified by this standard

Multi-channel operation(1/3)(1) PHY is tuned to the CCH, and receives WSAs, which are in turn passed to MLME, and then WME.(2) WME accepts user service requests from higher layer entities.(3) WME matches available services with requested services and assigns channel access, sending SCH start commands to the MAC layer management entities associated with the two physical layers.

Multi-channel operation(2/3)(4) MLME controls the channel switching of the two PHYs. PHY1 alternates between CCH and SCH1 on channel interval boundaries; PHY2 remains tunes to SCH2 for the duration of its service.(5) On receipt of a subsequent request from the higher layer, WMEends the SCH2 assignment and MLME in turn causes PHY2 to return to its default state.

Multi-channel operation(3/3)

Provide Functions(Channel routing)Routing for WSMP dataRouting for IP datagram(User priority, UP)(Channel coordination)MAC(MSDU)

Routing for WSMP data (1/2) WSMP header channel numberpower level data rateData Packet IEEE 1609.3

Routing for WSMP data (2/2) Routing Script Scenario WSMP data LLC MAC MAC buffer WSMP header channel number WSMP header channel number channel number CCH number SCH number

Routing for IP packet (1/2) IP MLME SCH numberpower leveldata rate power level data rate

IP LLC MACMACSCH

Routing for IP diagrams (2/2)Data shall be discarded WAVE WBSS (WAVE basic service set) WBSSWAVESCH

User priority (1/2)IEEE 802.11e (Enhanced Distributed Channel Access mechanism EDCA) (MAC) (access category index, ACI)IEEE 802.11 EDCA parameters(Arbitration inter-frame spaceAIFS)(Contention windowCW)(Transmit opportunity (TXOP) limit) TXOPlimit =0MSDU

User priority (2/2) Channel (MAC)LLCPHYMACACI = 0ACI = 1ACI = 2Transmit QueuesAIFS[ACI]CW[ACI]TXOP[ACI]Internal ContentionMedium ContentionSource : IEEE 1609.4AIFS[ACI]CW[ACI]TXOP[ACI]AIFS[ACI]CW[ACI]TXOP[ACI]ACI = 3AIFS[ACI]CW[ACI]TXOP[ACI]Pre-queue channel access functions

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-ITS

*DSRCITSDSRCOBURSU10MHz5.855~5.925GHz5.890GHz()5.860GHz()DSRC/WAVEIPIEEE1609.3/WAVE Short Message ProtocolIPv6 **IEEE1609 IEEE 1609 5.9 GHz IEEE 802.11 802.11p IPv6

IETF (Internet Engineering Task Force) WAVE LLC (Logical Link Control ) -- IEEE 802.2LLCMAC (Medium Access Control) -- PHY (Physical Layer) -- WME (WAVE Management EntityWAVE )MLME (MAC Layer Management Entity)PLME (Physical Layer Management Entity)WSMP (WAVE Short Message ProtocolWAVE )MAC sublayer management entity (MLME)physical sublayer management entity (MLME)

WAVE(RSU)(OBU)****

*** WAVE-- WSMP IPv6- CCH shorthigh-priority application system control message - SCH *WAVE- WSMP WSMPWSMPWAVE (CCH or SCH) PHY()WSMsMAC addressbroadcast addressWSMs PSID WSMs - IPv6SCH *IEEE 1609.3 WAVE system IP non-IP based non-IP basedWSMPIEEE 1609.3 WAVE WME MIB LLCUDP/TCPWSMP LLCIEEE 802OSIMACLLCIEEE 802.3MACLLCIEEE 802.2LLC DSAP(Destination Service Access Point)SSAP(Source Service Access Point)(Control)DSAPSSAP DSAPSSAP SNAP(Sub-Network Access Protocol)LLC HeaderDSAPSSAP64SNAP CodeTypeCodeTypeEthernet IITypeSNAPLLCDSAP SSAP0XAAControl0X03 IPv6Ethernet Type0x86DD

WSMEthernet Type0x88DC CCHCCH intervalSCH intervalCCHSCHNetworking ServicerequestSCHCCH intervalCCHSCH intervalService access point (SAP)protocol layer*WSIE WAVEWMEProvider Service InfoChannel InfoWAVE Routing Advertisement WRA()WAVE Service Advertisement WSA IEEE 1609.2Security HeaderTrailerSecured WSApackageMLME-WSA.requestMLMEMLMEtiming quality headerWSIEMAC header trailer Higher layerentityprovider service request WMESCHMLMEWSAs Higher layerentityuser service requestSCHWMEWSAsdetectSCHHigher layerentityuser service request no SCH accessWMEWSAsHigher layerHigher layerMIBservice requestauto-accessWMEauto-accessSCH accessHigher layerentity user servicerequestWMEMIBWMESCH accessProvider Service InfoService InfoChannel InfoWAVE RoutingProvider Service Identifier (PSID) WSM

WAVE Element IDWSMElement ID

WSMLength WSM data

WSMData WSMDataWAVE Element ID**IEEE 1609.4 MLME WAVE MAC with channel coordination MLME MAC (MAC sublayer management entity) (multi-channel) IEEE 802.11 MACLLC (logical link control IEEE802.2) PHY (IEEE P802.11p)

PHYCCHWSAsMLMEWMEWMEWMEMLMEPHYMLMEPHYPHY1CCHSCH1channel intervalPHY2SCH2WMESCH2PHY2default*WSMP (WAVE short message protocol) data WSMP header , Channel numberPower level Data rate1 octet = 8

*WSMP (WAVE short message protocol) data 1. WSMP data LLC MAC 2. MAC buffer WSMP header channel number3. WSMP header channel number channel number CCH number SCH number* IP IP MLME SCH numberpower leveldata rate power level data rateIP LLC MACMACSCH

* WAVE WBSS (WAVE basic service set) WBSSWAVESCH

* Channel (PHY) MSDU MAC Channel routing MAC (ACI) (back-off)

ITS1986U. C. BerkeleyPATHVIIGMV2VIVBSS(Integrated Vehicle-Based Safety System)CICAS(Cooperative Intersection Collision Avoidance System)VII(Vehicle Infrastructure Integration)(Vehicle Safety Communication Consortium, VSCC)*ITS1970ASV(Advanced Safety Vehicle)AHS(Advanced cruise-assisted Highway System)*FleetNetIVHW (Inter-Vehicle Hazard Warning)CarTALK 2000WILLWARN (Wireless Local Danger Warning)COMeSafetyIntelligent Car Initiative2003 (C2C-CC, Car-to-Car Communication Consortium)*