Communication Principles State of the Art

1. Communication PrinciplesState of the Art • Infrastructure based networks are already deployed • Currently, only safety applications have technical demand for vehicle-2-vehicle communication • Cellular communication is even getting better with LTE / LTE Advanced  Latency goes down • Aktiv CoCar: for most applications cellular network is usable • Motivation for direct Vehicle-2-Vehicle communication? • Low delay ( safety applications) • General communication over V2V (risk of overload for cellular networks?) • Cost reduction ( no network operator to pay) • Current state of the art assumes car-2-car/car-2-infrastructure == WLAN 802.11p • We should separate communication principles from communication technologies! • Avoid dependence on one particular technology

2. Communication PrinciplesState of the Art • Location Based Services • Currently implemented by cellular technologies • Possibly new business models could enable vehicle-to-infrastructure communications, e.g. grocery store pays for road-side-unit since it is also used for advertising • Vehicle-to-Vehicle communication research • Safety applications • Traffic efficiency applications • Monitoring environmental conditions (pollution, weather, fuel consumption, …) • Communication Patterns • Periodic Broadcast (Beaconing) • Store-Carry-Forward

3. Communication PrinciplesState of the Art • Communication Characteristics • Local communication • Low Latency • Typical: • One-hop Broadcast • Small packets (Beacons): Speed, latency, direction,…  DSRC • Beaconing mechanisms • Adapt rate • Adapt transmission power • Design principles • Robustness against packet loss, complete loss of link • Minimize the probability of packet loss  or  design to cope with packet loss

4. Communication PrinciplesState of the Art • What is the relation of cellular communication and vehicle-to-vehicle communication • Competitors or one extends/replaces each other • Avoid dependence on cellular infrastructure (safety applications: car needs to be autonomous!) • Does the game change with electric vehicles? • Value of correct information (traffic congestion, height data) increases • Frequency used for car-2-car communications • Most current works assume GHz (2.4, 5.9…) • Communication would look much different if we shift to e.g. 600 MHz  LOS not a problem • Combination of high speed GHz communication with low speed communication at lower frequencies? • For safety, we do not need high rates but reliability and wide range

5. Communication PrinciplesState of the Art • Car-2-Car Communication • For safety applications only • Or: use spare capacity for other applications? • Can VANET patterns be applied to other domains? • Pedestrians with cell phones (tests indicate that beaconing will only increase power by 1-2%) • Bicycles (with bicycle OBU or mobile device) • Data Dissemination • Geocast / directed broadcast • Unicast up to an area, broadcast afterwards? Applications? • Where do we perform re-broadcasting of information? (network layer, transport layer, app layer?) • Even end-to-end on a small scale? • Other topic: directional antenna applications

6. Vielen Dank.