Platooning Enabled by ETSI ITS-G5 Communications: Fuel Efficiency Analysis

Platooning Enabled by ETSI ITS-G5 Communications: Fuel Efficiency Analysis Nikita Lyamin, Alexey Vinel {nikita.lyamin, alexey.vinel}@hh.se Halmstad University 1 / 30

We make an attempt to evaluate the performance of platoon enabled by contemporary ITS-G5 vehicular communications 2 / 30

System Model communication range Car N-1 Car N-2 Car 2 Car 1 Leading vehicle N vehicles 3 / 30

ETSI ITS-G5 Facilities layer ETSI CAM triggering Access layer ETSI DCC IEEE 802.11p MAC IEEE 802.11p PHY ITS-G5 4 / 30

First, we study the performance of ETSI EN 302 637 2 CAM in CACC/Platooning scenario 5 / 30

System Model communication range Leading Car N-1 Car N-2 Car 2 Car 1 vehicle N vehicles Each vehicle: generates CAMs in accordance to the ETSI EN 302 637-2 Specification of Cooperative Awareness Basic Service ; 6 / 30

Reference mobility scenario 30 Platoon's speed pattern Speed, m/s 25 20 15 factor(nodeid) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 10 100 150 200 250 300 Time, s 7 / 30

Communication setup: ETSI EN 302 637-2 CAM Facilities layer Access layer ETSI CAM triggering ETSI DCC IEEE 802.11p MAC IEEE 802.11p PHY ITS-G5 CAM shall be triggered in one of two cases: The time elapsed since the last CAM generation is equal or larger than T max = 1000 ms. The time elapsed since the last CAM generation is equal or larger than T min = 100 ms and any of the following events has occurred: 1. Event A : the absolute difference between the current position of the vehicle and its position included in the previous CAM exceeds d min =4 m; 2. Event B : the absolute difference between the current speed and the speed included in the previous CAM exceeds υ min =0.5 m/s; 3. Event C : the absolute difference between the current direction of the vehicle and the direction included in the previous CAM exceeds 4. 8 / 30

Identified problem CAMs Generation Moments: Synchronization speed of the platoon, m/s 25 24 23 22 21 20 19 18 0 10 20 30 40 50 60 70 80 time, s Event A V 1 V 2 V 3 V 4 V 5 V 6 V 7 V 8 V 1 V 2 V 3 time Constant speed d min / Event A : d min =4 m; Event B : υ min =0.5 m/s; 9 / 30

Identified problem CAMs Generation Moments: Synchronization speed of the platoon, m/s 25 24 23 22 21 20 19 18 0 10 20 30 40 50 60 70 80 time, s T min Event A Event B V 1 V 2 V 3 V 4 V 5 V 6 V 7 V 8 V 1 V 2 V 3 V 4,5,6 V 7 V 8 V 1 V 2 V 3 t: min time Constant speed d min / Speed starts to change T min Event A : d min =4 m; Event B : υ min =0.5 m/s; 10 / 30

IEEE 802.11p Groups > Collisions 0.7 speed of the platoon, m/s Before maneuvers After 1 st maneuver After 2 nd maneuver After 3 rd maneuver After 4 th maneuver 25 24 23 22 21 20 19 18 0 50 100 150 200 250 300 time, s Collision probability 0.6 0.5 0.4 0.3 0.2 = σ = 500σ = σ and δ = uniform[0,500σ] = 200σ and δ = uniform[0,500σ] 0.1 0 before maneuvers after 1st maneuver after 2nd maneuver after 3rd maneuver after 4th maneuver Figure : CAM collision probability 11 / 30

We make an attempt to evaluate the fuel efficiency of platoon enabled by contemporary ITS-G5 vehicular communications 12 / 30

System Model communication range Leading Car N-1 Car N-2 Car 2 Car 1 vehicle N vehicles Each vehicle: generates CAMs; 13 / 30

System Model communication range Leading Car N-1 Car N-2 Car 2 Car 1 vehicle N vehicles Each vehicle: generates CAMs; restricts CAMs transmission in accordance to the Decentralized Congestion Control Mechanisms for ITS-G5; 13 / 30

Reference mobility scenario 30 Platoon's speed pattern Speed, m/s 25 20 15 factor(nodeid) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 10 100 150 200 250 300 Time, s We test both: Scenario 1: platoon of passenger vehicles; Scenario 2: platoon of HDVs. 14 / 30

Communication setup: ETSI DCC Facilities layer ETSI CAM triggering Access layer ETSI DCC IEEE 802.11p MAC IEEE 802.11p PHY ITS-G5 According to ETSI TS 102 687: Decentralized congestion control (DCC) is a mandatory component of ITS-G5 stations operating in ITS-G5A and ITS-G5B frequency bands to maintain network stability, throughput efficiency and fair resource allocation to ITS-G5 stations. 17 / 30

Communication setup: ETSI TS 102 687, TR 101 612 DCC Configurations Relaxed Active Restrictive 10Hz CBR 0.15 2Hz CBR 0.4 1Hz Communication setup 1: ETSI TS 102 687 Configuration Relaxed Active1 Active2 Active3 Active4 Active5 Restrictive 16.7Hz 10Hz 5.6Hz 3.8Hz 2.9Hz 2.4Hz 2.2Hz CBR 0.19 CBR 0.27 CBR 0.35 CBR 0.43 CBR 0.51 CBR 0.59 Communication setup 2: ETSI TR 101 612 Configuration 18 / 30

Plexe: platooning simulator Plexe simulator includes: Wireless V2V IEEE 802.11p communications (Omnet++) Mobility simulator (SUMO) Simulation of a control system (Controller: each vehicle feeds acceleration and speed of leader and car directly in front in the controller in order to keep desired inter-vehicle distance.) 19 / 30

Plexe: platooning simulator We additionally implemented: CAM ETSI EN 302 637-2 DCC ETSI TS 102 687, TR 101 612 20 / 30

Platooning fuel-consumption model f = tf t 0 [ ] δ (µcosθ + sinθ)mgv + κv 3 + Mav dt Hη (1) Where the air-drag coefficient κ is computed from: κ = 1 2 ρaaac D(1 φ) (2) Q. Deng, A General Simulation Framework for Modeling and Analysis of Heavy-Duty Vehicle Platooning, in IEEE Transactions on Intelligent Transportation Systems, vol.pp, no.99, pp.1-11 21 / 30

Performance evaluation: air-drag reduction 9.75 9.7 Fuel Economy [L/(100*km)] 9.65 9.6 9.55 9.5 9.45 9.4 9.35 No Platooning Communication Setup 1 Communication Setup 2 9.3 9.25 0 5 10 15 Position of Vehicle in Platoon Figure : Fuel efficiency. Scenario 1: platooning of passenger vehicles. Conclusion: passenger cars usually do not have fuel saving incentive to form platoons. 22 / 30

Performance evaluation: air-drag reduction 68 Fuel Economy of HDV [L/(100*km)] 67 66 65 64 63 No HDV Platooning Communication Setup 1 Communication Setup 2 62 0 5 10 15 Position of Vehicle in Platoon Figure : Fuel efficiency. Scenario 2: platooning of HDVs. Communication Setup 1 results in 2.1% 6.4% improvement in fuel economy, and Communication Setup 2 further enhances the improvement to 2.1% 6.8%, indicating that platoon communication setup also plays an important role in fuel consumption. 23 / 30

Performance evaluation: inter-vehicle distance in platoon Inter-vehicle distance in the platoon 11 9 7 5 3 1 Scenario 1 Scenario 2 Communication Setup 1 Communication Setup 2 Communication Setup 1 Communication Setup 2 Figure : Platoon Inter-vehicle distance. The enhanced fuel efficiency in Communication Setup 2 is a result of platoon s ability to maintain required inter-vehicle gap with higher precision under this scenario comparing to Communication Setup 1. 24 / 30

Performance evaluation: inter-vehicle distance 10 9 8 7 6 5 4 3 2 1 10Hz_DCC_2+1 20Hz_DCC_2+1 30Hz_DCC_2+1 ETSI_CAM_DCC_2+1 10Hz_DCC_2+3 20Hz_DCC_2+3 30Hz_DCC_2+3 ETSI_CAM_DCC_2+3 10Hz_DCC_2+5 20Hz_DCC_2+5 30Hz_DCC_2+5 ETSI_CAM_DCC_2+5 Figure : Platoon Inter-vehicle distance for different DCC/CAM configurations. 25 / 30

Performance evaluation: numerical experiment on European route E4 Tornio Helsingborg Figure : European Route E4. The European route E4 passes through 22 cities of Sweden with a total length of 1590km. There are two on-ramps and off-ramps from/to each of the 22 cities, the speed limit for on- /off-ramp is 60km/h. Since HDV is restricted to drive on the truck lane at the rightmost, the platoon has to decelerate to 60km/h in the ramp area and accelerate to desired speed 90km/h afterwards. 26 / 30

Performance evaluation: numerical experiment on European route E4 Table : Estimated Overall Fuel Economy and Yearly Total Cost of 15-HDV Platoon Communication No HDV Communi. Communi. Setup Platooning Setup 1 Setup 2 Fuel Economy (L/100km) 36.79 30.54 30.31 Yearly Total Cost (MSEK) 15.89 13.11 13.09 Note, the results from numerical experiment largely depend on the number of disturbances occurred in front of the platoon leader during operation. 27 / 30

Summary. Current progress. A. Vinel, L. Lan, and N. Lyamin, Vehicle-to-Vehicle communication in C-ACC/Platooning scenarios, IEEE Communications Magazine, p. 192 197, 2015. N. Lyamin, A. Vinel, and M. Jonsson, Does ETSI Beaconing Frequency Control Provide Cooperative Awareness? Proc. IEEE ICC 2015 Workshop on Dependable Vehicular Communications (DVC), London, UK, June 2015, pp. 10 459 10 464. Lyamin, N., Deng, Q., Vinel, A., Study of the Platooning Fuel Efficiency under ETSI ITS-G5 Communications. 2016 IEEE 19th International Conference on Intelligent Transportation Systems, 2016 (Accepted) 28 / 30

Questions? THANK YOU FOR YOUR ATTENTION! 30 / 30