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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
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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 communicationbetweenvehicles • 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