Automotive Communication via Mobile Broadband Networks

Automotive Communication via Mobile Broadband Networks Dr. Joachim Sachs Ericsson Corporate Research, Aachen Contributors: René Rembarz, Mai-Anh Phan, Sabine Sories

Where are we in telecommunications? Global Connectivity PLACES ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 2

Where are we in telecommunications? Digital Society Sustainable World Personal Mobile Global Connectivity PEOPLE PLACES 5.0 Bn ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 3

Where are we in telecommunications? THINGS 50 Bn Digital Society Sustainable World Personal Mobile Global Connectivity PEOPLE PLACES 5.0 Bn ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 4

Where are we in telecommunications? THINGS 50 Bn Joachim Sachs, Mobile Internet Access über GPRS und UMTS, 1 st Zukunft der Netze, 1999 GPRS: 10s 100s kb/s UMTS: 100s kb/s 1 Mb/s PEOPLE 5.0 Bn PLACES ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 5

One decade of UMTS/HSPA evolution HSPA peak data rates [Mb/s] 7 21 28 42 15 codes, 64 QAM 10 codes, 16 QAM MIMO 84 Multi Carrier 168 Combinations THINGS PEOPLE 50 Bn 5.0 Bn PLACES ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 6

One decade of UMTS/HSPA evolution HSPA peak data rates [Mb/s] 7 Further increase 42 with 28 LTE MIMO 21 15 codes, 64 QAM 10 codes, 16 QAM 84 Multi Carrier 168 Combinations THINGS PEOPLE 50 Bn 5.0 Bn PLACES ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 7

Machine-to-machine and the Networked Society everything that benefits from a network connection will have one THINGS 50 Bn PEOPLE 5.0 Bn PLACES ~0.5 Bn 1875 1900 1925 1950 1975 2000 2025 Source: Ericsson Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 8

Why should cars communicate? Fatalities Billion kilometers per year Constant decrease despite increasing traffic volumes Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 9 Source: German Federal Statistical Office

Why should cars communicate? Communicate ACC Lane assist See Seat belts ABS Airbags ESP Feel Passive Safety Next big step in vehicle safety through communication Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 10

ETSI Standardization C-ITS Cooperative Intelligent Transport Systems Goals, e.g.: Improved traffic efficiency Increased road safety Automotive Messaging Types CAM Cooperative Awareness Message DEN Decentralized Environmental Notification Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 11

Cooperative Awareness Message CAM - Use Cases Use Case Min frequency (Hz) Max latency (ms) Emergency Vehicle Warning 10 Intersection Collision Warning 10 Collision Risk Warning 10 Slow Vehicle Indication 2 Motorcycle Approaching Indication 2 Traffic Light Optimal Speed Advisory 2 Speed Limits Notification 1 to 10 100 Intersection assistance Sent by vehicle or roadside unit Periodically transmitted Vehicle information (position, direction, velocity, ) Destination: neighboring hop Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 12

Decentralized Environmental Notification DEN Use Cases Use Case Triggering condition Terminating condition Latency (s) Emergency electronic brake light Collision risk warning Stationary vehicle accident Stationary vehicle vehicle problem Hard braking of a vehicle Detection of a turning/crossing/merging collision by roadside unit ecall triggering Vehicle breakdown or vehicle with activated warnings Automatically after the expiry time End of collision risk Vehicle involved in accident is removed Vehicle is removed from the road 0.2 0.2-1 s Traffic jam warning Traffic jam detection End of traffic jam < 5 Road work warning Signalled by fixed or End of road work > 1 min moving roadside station Precipitation Detection of a heavy rain or snow (activation of windscreen wrappers) Detection of the end of the heavy rain or snow situation < 5 Road adhesion Detection of a slippery road condition (ESP activation) Detection of end of the slippery road condition < 5 < 5 < 5 Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 13

Decentralized Environmental Notification DEN Use Cases Use Case Triggering condition Terminating condition Latency (s) Emergency electronic Hard braking of a vehicle Automatically after the 0.2 brake light expiry time Collision risk warning Detection of a End of collision risk 0.2-1 s Main usage Road turning/crossing/merging Hazard Warnings (RHW) collision by roadside unit Stationary Sent vehicle when road hazard ecall triggering is detected Vehicle involved in < 5 accident accident is removed Stationary vehicle event based Vehicle (road breakdown hazard or exists) Vehicle is removed from < 5 vehicle problem vehicle with activated the periodic repetition and continuous broadcast warnings Traffic jam warning (until expiry Traffic or termination jam detection message) End of traffic jam < 5 Road work Distribution warning to Signalled vehicles by fixed within or a relevance End of road area work > 1 min moving roadside station Precipitation Detection of a heavy rain or snow (activation of windscreen wrappers) Detection of the end of the heavy rain or snow situation < 5 Road adhesion Detection of a slippery road condition (ESP activation) Detection of end of the slippery road condition < 5 Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 14

Car-to-car using dedicated short range radio (DSRC)! Traffic Management Center Why not use cellular? 802.11p in 5.9 GHz availability, coverage and performance Roadside equipment every 500-1000 meters Highway networks US: 75000 km Germany: 12000 km Sweden: 1800 km Rural and urban not included Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 15

Cooperative cars projects Cooperative Cars (CoCar, 2006-2009) Basic research on cellular car-to-car communication using UMTS and HSPA Reference case: Road Hazard Warnings Cooperative Cars extended (CoCarX, 2009-2011) LTE, session management, heterogeneous approach Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 16

Car-to-car over cellular! Hazard Warning accident, emergency breaking, bad road condition, road works, slow vehicle Traffic Management Center! Core Network Infrastructure Filtering/ GeoMessaging! Traffic Information updates traffic condition & warnings! NodeB Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 17

Cellular car-to-car delay AS Core WAN UMTS 2009 HSPA 2011 LTE 2011 Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 18

Cellular car-to-car delay AS Core Delay requirements can be met with LTE (and largely with HSPA) WAN UMTS 2009 HSPA 2011 LTE 2011 Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 19

How about system capacity? Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 20

LTE Capacity evaluation methodology LTE radio network simulations Full protocol stack and mobility simulated Network size: 9 cells, 3 sites System bandwidth: 5 MHz for UL and DL Intersite-distance (ISD) and carrier frequency A: 500 m at 2 GHz B: 6 km at 800 MHz Tx / Rx antennas: 1 / 2 (SIMO) Over 5000 cars simulated User speed: 13.9 m/s = 50 km/h Message sizes based on ETSI DENM/CAM (120 byte) No cross traffic Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 21

LTE Capacity evaluation Case 1: Periodic messages Mobile Network CoCarX Backend 1. 2. broadcast Communication through network infrastructure and backend 1. Sender behavior All cars sending CAM, 2 Hz and 10 Hz compared 2. Message distribution CAM to all receivers in same cell immediately congests network Regional filtering modeled CAM distributed to 10 or 40 vehicles in the vicinity Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 22

Average vehicle-to-vehicle delay [s] Average vehicle-to-vehicle delay [s] CAM V2V delay Urban vs. Rural environment 1.6 1.4 1.2 1.0 2 GHz, 500 m ISD 10 Hz, 40 neighbors 10 Hz, 10 neighbors 2 Hz, 40 neighbors 2 Hz, 10 neighbors V2V delays < 100 ms 0.8 0.6 0.4 0.2 0 0 50 100 150 200 250 300 350 400 Average number of vehicles per cell 1.6 1.4 1.2 1.0 0.8 0.6 0.4 800 MHz, 6 km ISD 10 Hz, 40 neighbors 10 Hz, 10 neighbors 2 Hz, 40 neighbors 2 Hz, 10 neighbors Scenario UL+DL 10 Hz 40 neighbors UL+DL 10 Hz 10 neighbors UL+DL 2 Hz 40 neighbors UL+DL 2 Hz 10 neighbors N vehicles per cell urban 13 rural 9 urban 57 rural 47 urban 67 rural 49 urban 275 rural 199 0.2 0 0 50 100 150 200 250 300 350 400 Average number of vehicles per cell Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 23

Average vehicle-to-vehicle delay [s] Average vehicle-to-vehicle delay [s] CAM V2V delay Urban vs. Rural environment 1.6 1.4 1.2 1.0 2 GHz, 500 m ISD 10 Hz, 40 neighbors 10 Hz, 10 neighbors 2 Hz, 40 neighbors 2 Hz, 10 neighbors V2V delays < 100 ms 0.8 0.6 0.4 Downlink capacity 0.2 quickly reached (5MHz spectrum) 0 0 50 100 150 200 250 300 350 400 Average number of vehicles per cell 800 MHz, 6 km ISD 1.6 10 Hz, 40 neighbors reduce 1.4 transmit frequency 10 Hz, 10 neighbors 2 Hz, 40 1.2 reduce # neighbors 2 Hz, 10 neighbors 1.0 0.8 0.6 0.4 Scenario UL+DL 10 Hz 40 neighbors UL+DL 10 Hz 10 neighbors UL+DL 2 Hz 40 neighbors UL+DL 2 Hz 10 neighbors N vehicles per cell urban 13 rural 9 urban 57 rural 47 urban 67 rural 49 urban 275 rural 199 0.2 0 0 50 100 150 200 250 300 350 400 Average number of vehicles per cell Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 24

LTE Capacity evaluation Case 2: Warning messages (DENM) Mobile Network CoCarX Backend 1. 2. g pwlan broadcast le hops) Communication through network infrastructure and backend 1. Sender behavior 1, 10, 20, 40 cars per cell sending DENM with average 1 Hz 2. Message distribution Simple GeoMessaging abstraction used DENM sent to all vehicles in same cell (easy to implement) Substantial potential for optimization (e.g. duplicate filtering in backend) Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 25

Average vehicle-to-vehicle delay [s] Average vehicle-to-vehicle delay [s] DEN V2V delay Urban vs. Rural environment 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 40 incidents 20 incidents 10 incidents 1 incident 2 GHz, 500 m ISD 0 0 100 200 300 400 500 600 Average number of vehicles per cell 1.6 1.4 1.2 1.0 0.8 0.6 0.4 800 MHz, 6 km ISD 40 incidents 20 incidents 10 incidents 1 incident V2V delays < 200 ms Scenario UL+DL 1 incident UL+DL 10 incidents UL+DL 20 incidents UL+DL 2/s 40 incidents N cars per cell urban 2500 rural 2250 urban 550 rural 400 urban 280 rural 200 urban 140 rural 100 0.2 0 0 100 200 300 400 500 600 700 Average number of vehicles per cell Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 26

Average vehicle-to-vehicle delay [s] Average vehicle-to-vehicle delay [s] DEN V2V delay Urban vs. Rural environment 1.6 1.4 1.2 1 0.8 0.6 More than 100-2000 0.4 0.2 40 incidents 20 incidents 10 incidents 1 incident 2 GHz, 500 m ISD cars per cell with delay <200ms 0 0 100 200 300 400 500 600 Average number of vehicles per cell 1.6 1.4 1.2 1.0 0.8 0.6 0.4 800 MHz, 6 km ISD Temporary load 40 incidents 20 incidents 10 incidents 1 incident V2V delays < 200 ms Scenario UL+DL 1 incident UL+DL 10 incidents UL+DL 20 incidents UL+DL 2/s 40 incidents N cars per cell urban 2500 rural 2250 urban 550 rural 400 urban 280 rural 200 urban 140 rural 100 0.2 0 0 100 200 300 400 500 600 700 Average number of vehicles per cell Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 27

Conclusion CAM could in theory be supported by LTE networks High radio resource usage for little new information Heavy backend filtering required Can 802.11p cope with this load? DEN can efficiently be supported by LTE networks Warning essential to increase road safety Delay requirements can be met Capacity only needed in case of incident temporary effect Requires intelligent backend filtering for distribution in relevance area Possible capacity improvements Solution using Multimedia Broadcast Multicast Service Other important vehicular communication use cases much easier Remote diagnostics, road traffic management, Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 28

Complementary solutions? cellular and ad-hoc DSRC Cellular communication Ad-hoc communication Traffic information Remote Navigation Cooperative traffic lights Lane change assistant Software download Hazard warnings Remote Diagnostics Intersection assistant Infotainment (NLOS) 2G (EDGE) 3G (HSPA) 4G (LTE) Collision avoidance (LOS) 802.11p (ad-hoc) Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 29

References G. Jodlauk, R. Rembarz, Z. Xu: 'An Optimized Grid-Based Geocasting Method for Cellular Mobile Networks', to appear at ITS World Congress 2011, Orlando, Florida, October 2011. M. Phan, R. Rembarz, S. Sories: 'A Capacity Analysis for the Transmission of Event and Cooperative Awareness Messages in LTE Networks', to appear at ITS World Congress 2011, Orlando, Florida, October 2011. D. Westhoff (ed.), "ITS Services and Communication Architecture", Cooperative Cars extended (CocarX) project deliverable D3, September 2011. Joachim Sachs Zukunft der Netze 2011 Ericsson AB 2011 2011-09-30 Page 30