Distributed and Adaptive Communication Protocols for Autonomous Vehicles

1. Distributed and Adaptive Communication Protocols for Autonomous Vehicles Greg Pottie Charles Taylor

2. Outline • Reliable communication links • Exploitation of redundancy • Interaction with control hierarchy • Development of robust, adaptive message sets

3. Reliable Communication Links • Robust, jam-resistant communications (ONR project): • Spread spectrum • Channel coding and retransmission • Adaptive power control and bit rate • Adaptive antenna arrays • Fast adaptation through interpolation

4. Trades • Delay—shorter delay implies less robust coding and adaptation • Data rate—higher data rate demands more resources • Security—higher security implies reduced communications flexibility • Error rate—lower error rate demands increased complexity

5. Exploitation of Numbers • Variable link quality often acceptable if have routing choices • Groups of autonomous vehicles may tolerate variable quality of service

6. Interaction with Control Hierarchy • Control hierarchy implies variable message priority, quality of service • Delay • Error rate targets • Data rate • Maximum time between control updates • Demands new model for communications traffic and thus possibly new MAC

7. Control Traffic Models Within formation: Low latency, high rate, predictable locations, response to local conditions Between formations: High latency, low rate, location uncertainty, global objectives

8. Evolving Control Language • Different layers of control hierarchy will demand different message sets; want these to be robust and to describe the phenomena of interest • Limited set of events of interest at each level may permit automated evolution of languages

9. Language Construction • Bind utterances (description/meaning pairs) to events of interest; this builds the basic vocabulary • Determine the logic underlying the relationships between the events; this underpins the grammar of the language • Language builds in understanding and thus is a form of compression

10. Logic of Language • The events of interest and the certainty with which they are observed imply different logics for inference • Logic takes into account unreliability of individual links, and considers actions of group as a whole

11. Preliminary research • Abstract model for constrained set of events—needed also for traditional communications protocol construction • Extract vocabulary and logic • Build grammar • Aim is to gradually consider more complicated situations, to determine whether languages can be automatically evolved to deal with unexpected events.