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Radio Transmission Technology for V2V/V2I Applications. Date: 2008-07-17. Authors:. Slide 1. contents. 1. V2V/V2I Applications. 2. Service Requirements. 4. 3. 5. Performance Simulation. Proposed Technologies. Summary. V2V/V2I Applications. GPS.
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Radio Transmission Technology for V2V/V2I Applications Date: 2008-07-17 Authors: Slide 1
contents 1 V2V/V2I Applications 2 Service Requirements 4 3 5 Performance Simulation Proposed Technologies Summary
V2V/V2I Applications GPS • V2V Communication : Vehicle Multi-hop Networking for Vehicle Safety • V2I Communication : Bi-directional Packet Communication for ITS/Telematics Cellular/WiBro TSP Server Internet RSE RSE Emergency Message Warning Message Warning Message V2V Traffic Information V2I Probe Data Hopping Accident
V2V Service Use Case Warning Message Broadcasting Detect accident or road status in real time & broadcast warning message to the following vehicle by using vehicle to vehicle multi-hop communication ③ Vehicle 3 ② Vehicle 2 ① Vehicle 1
V2I Service Use Case Traffic Information Center Backbone Network • Probe data collection/Traffic information • RSE collects probe data from the vehicle periodically • and provides traffic and road status information to vehicles Road/Traffic Information Probe data collection Traffic Probe Vehicle Road/Traffic Information
Basic Requirements Communication : Broadcasting, Unicasting Mobility : Max. 200 km/h Packet Latency : < 100 msec Long packet transmission : ~1kbytes Networking : V2I or VANET Service Requirements Traffic Management or Other Center Traffic Management Center Server/ Network Interface ITS/Telematics Application RSU Antenna Internet or Private Network Two-way RF Roadside Unit (RSU) Roadside Host Processor and Backhaul Equipment Inside Equipment Cabinet Frequency (GHz)
Proposed Technologies Mid-amble based Channel Estimation in Vehicle Mobility . Conventional : Preamble or Pilot Sub-carriers based Initial Channel Estimation - Problem : Performance degraded for long packet reception because it providesonly initial time and channel phase acquisition . New : Mid-amble based Channel Estimation and Tracking - Benefits : Good performance for long packet reception because it provides initial and continuous time and channel phase acquisition N symbol Preamble Payload Payload Midamble Payload Payload Midamble Payload Payload ∙∙∙ ∙∙∙ ∙∙∙ Equalizer Equalizer Equalizer Channel estimation Channel Estimation & Update Channel Estimation & Update
Proposed Technologies • CSMA/CA-TDMA combined MAC with priority control • Conventional : CSMA • - Problem : Throughput degradation for the increased number of users • New : CSMA/CA-TDMA combined MAC • - Benefits : Better throughput by time slot scheduling, useful for VANET and V2I
Performance Simulation Radio Link Simulation . Transceiver model : IEEE 802.11p with Mid-amble insertion . Radio Channel Model : TDL filter model, which was proposed by GIT, USA . Comparative analysis : Performance of Preamble based or Mid-amble based channel estimation
Performance Simulation Packet Length Analysis of Preamble based Estimation . If packet length is less than 40 bytes, its performance is good. However, its performance will be worse as the packet length is increasing . Long sized packet to be order of 1kbytes : needs new technology for V2I applications
Performance Simulation Radio Link Simulation for 200 bytes packet . Fading Loss : approximated 20 dB if channel estimation is perfect . Mid-amble channel estimation performance for BPSK/16QAM modulation : approaches performance of ideal channel estimation even though it is impacted by radio channel models
Performance Simulation Radio Link Simulation for 1 Kbytes packet . Mid-amble channel estimation for BPSK/16QAM: approaches performance of ideal channel estimation, uniform performance irrespective of modulation level
Performance Simulation MAC simulation • PHY : 802.11a OFDM, 6Mbps fixed • MAC : 802.11 DCF, CSMA/CA-TDMA combined MAC • Number of slot : 4 slots for CSMA/CA-TDMA combined MAC • Application : CBR Traffic (Unicast, Broadcast) • Simulation tool : Qualnet 4.0 version 10, 20. 30, 40 broadcast flows 5, 10, 15, 20 unicast flows
Performance Simulation Unicast Scenario • Unicast CBR Flows : 5~20 • Performance parameter : Throughput & Delay Throughput (bps) Delay [sec] Number of flows Number of flows
Performance Simulation Unicast Scenario • Unicast CBR Flows : 5~20 • Performance parameter : No of Retransmission (RTS) No. of retransmission No. of retransmission Number of flows Node ID Information
Performance Simulation Broadcast scenario • Broadcast CBR Flows : 10 ~40 • Performance parameter : Throughput & Delay Throughput (bps) Delay (sec) Number of flows Number of flows
Vehicle Serviceswill be categorized into V2V based Vehicle Safety Service : Intersection Collision Avoidance V2I bases Convergence Service : ITS/Telematics/USN Convergence Service V2V/V2I Communication has basic requirements High Mobility : 200 Km/h Low Latency : <100 msec Long Packet Transmission : ~ 1kbytes Networking : VANET or V2I Propose New Challenging Technologies Mid-amble based Channel estimation for long packet CSMA/CA-TDMA combined MAC for service priority Summary