Sentient Transportation Systems [Using sensor networks for building a full fledged transportation system for a township] Mobile Computing Class CEN 5531 Fall 2006 Sundara Dinakar Moumita Ghosh Shreyas Dube

Sentient Transportation Systems Sentient Systems Sentient Transportation Systems Integration of application areas: – "Drivers Domain“ Navigation Road and traffic information – "Passenger Domain“ Entertainment Information on vehicle performance Nice driving experience

Drivers domain – Navigation Before a journey, vehicles are notified about the virtual circuit (GPS ) waypoint information, vehicle builds RTImage (real-time perception) The cooperation between vehicles is critical to avoid collisions (through sensors) CORS (Continuously Operating Reference Stations) A Dead-Reckoning (DR) system kicks in to complement the GPS system

How do nodes communicate? City divided into zones – Event based communication between vehicles – Using publisher subscriber model – Vehicles have filters

Drivers domain – Congestion Control Access Points collect information about congestion in zones from vehicles traveling there Different Access Points from the same zone and different zones form a peer to peer network to exchange congestion information Vehicles record their speeds on each road, which when compared with the roads' speed limits gives an indication of the degree of congestion. On entering an area covered by a Wireless Access Point (AP), they report this data.

Inter-vehicle communication – MANET (Mobile Ad hoc Network) Ad hoc networks operate without a fixed infrastructure Multi-hop transmission Issues: – Limited power – Frequently changing topology

Multicast in MANET - Approaches Tree based – Group of core nodes run a multicast tree algorithm – Topology information needed – Not suitable for changing topology Mesh based – Uses a mesh to support multicast forwarding – Inefficient: Control overhead – Suitable for changing topology Flooding based – No Control overhead – Consumes too much network resource

RISP (Receiver-Initiated Soft-State Probabilistic multicasting protocol) The source node initiates a session by sending Beacon packets Upon receiving a Beacon, receivers send Join_REQ packets to join the multicast session and keep the session alive On receiving the first Join_REQ packet, the source begins to send data packets

Example Link failure Link addition

RISP – Conclusion RISP introduces probabilistic forwarding and soft- state for making relay decisions RISP can adapt to node mobility: – At low mobility, RISP performs similar to a tree-based protocol – At high mobility, it produces a multicast mesh in the network Simulation results show that RISP has a lower delivery redundancy than mesh-based protocols, while it achieves higher delivery ratio The control overhead is lower than other protocols

Infotainment A pleasant driving experience. – Nearest pizza shop – Automatic Up/Down of window shutters Information about the vehicle – Air pressure in the wheel – Oil leak - Brake failure  Achieved thru a well-planned sensory platform backed up with a powerful software framework.

Challenges in attaining infotainment: Pervasive system that enables seamless integration of mobile devices Web service connectivity / basic navigation / vehicle diagnostics. Upgradeable, flexible and reliable. Harsh conditions – extreme temperatures / dust / vibrations Graceful recovery from various faults. Performance Never cause a drain on the vehicle battery. Obedient to hard timing constraints regarding network bus responsiveness. Feature richness, Renewability, user interface. Prioritization of messages

The middleware – CAN (Controller Area network) protocol stack to deliver messages between Electronic Control Units (ECU). Prioritization of messages.

Characteristics Of Middleware Diagnostics Communication Services Device Management (over the air and USB) Power Management Speech Service Movement detection service Media player functionality GPS service

Finding obstacles in vehicles path Vision sensors to find change in the color of the terrain. Creation of context awareness

Passenger domain – Infotainment Automotive Platform Components

Passenger domain – Infotainment Automotive Platform Components consist of: – Hardware – Drivers – Operating System – Application Framework – HMI framework – Application HMI

Other uses of Sensors in the System Stop at traffic signals (without human control) Use of RFID in rental cars( for inventory control) Use vehicles as Environmental Sensors, to collect large geospatial database

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