doc.: IEEE /0832r1 Submission Woong Cho, ETRI July 2009 Slide 1 Enhancement Technology for Vehicular Communications Date: Authors:

doc.: IEEE /0832r1 Submission Woong Cho, ETRI July 2009 Vehicular Communications V2V(Vehicle-to-Vehicle) applications: – Vehicle safety via vehicle multi-hop communications V2I(Vehicle-to-Infrastructure) applications: –ITS/Telematics via bi-directional communications Basic requirements –Communication schemes: broadcasting, unicasting –Mobility: up to 200km/h –Long packet transmission:~2K bytes –Packet Latency: 100 msec < –Networking: V2I, V2V Slide 2

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Vehicular Communications Standard WAVE(Wireless Access in Vehicular Environments) –PHY/MAC: p –Upper layers: 1609.x p –PHY layer(10MHz Bandwidth) Uses scaled version of a-20MHz Defines sharp spectrum mask in transmission Defines enhanced channel rejection at the receiver –MAC layer Uses CSMA/CA of Uses AIFS(Arbitration InterFrame Space) in e for QoS supplement July 2009 Slide 3

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Some Drawbacks of p PHY layer –Channel estimation Adopts scheme, i.e., preamble based estimation, without any modification  Suitable for short packet transmission  Not sufficient for long packet transmission MAC layer –Collision Most safety applications use broadcasting  As the # of nodes increases, probability of collision increases –Fairness Unbalanced bandwidth requirements in V2I  CSMA/CA cannot provide differentiated channel access priority between RSEs and OBUs July 2009 Slide 4

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Enhancement Technology in PHY Need to guarantee long packet transmission –Modification of channel estimation –Ex) Midamble based channel estimation r1 “Radio Transmission Technology for V2V/V2I Applications” r0 “Channel Modeling and the Midamble Insertion Effects”  Verify the benefit of midamble based system July 2009 Slide 5

doc.: IEEE /0832r1 Submission Woong Cho, ETRI July 2009 Slide 6 Provide priority access –Consider TDMA-like system –Ex) Hybrid MAC: TDMA+CSMA/CA r1 “Radio Transmission Technology for V2V/V2I Applications” r1 “Hybrid MAC for VANET”  Hybrid MAC has better throughput than CSMA/CA Enhancement Technology in MAC

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Handover Issues Vehicles are move rapidly along roads  Handover occurs often, and handover issue becomes more important than  When OBU enters new RSE, it takes long channel scanning time to carry out handover p does not provide a sufficient answer for handover issue Fast handover scheme in vehicular network is needed to provide continuous communication between RSEs July 2009 Slide 7

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Next Step in Vehicular Communications Consider –Modification of PHY To support long packet transmission  Enable to provide various services –Modification of MAC To provide priority access  Solve collision problem and increase throughput –Fast handover To achieve continuous communication links  Provide communication environments with high quality July 2009 Slide 8

doc.: IEEE /0832r1 Submission Woong Cho, ETRI Straw Poll Yes : No : Don’t care : Need more information : July 2009 Slide 9 Q. Should IEEE WNG receive further presentations on the topic of enhancement technology for vehicular communications?