Maintaining Optimal Communication Chains Robotic Sensor Networks using Mobility Control

Electronic chaining is the formation, and maintenance, of a linked communication chain that maximizes the endto- end throughput using a cooperative team of mobile robotic relays. For this paper, an optimal communication chain is defined using the signal-to-noise ratio (SNR) of the communication links along the chain. By using the SNR of the individual communication channels, instead of relative position, an optimal communication chain of robotic relays is formed that is able to respond to changes in, and unexpected features of, the RF environment that is simply not possible with position based chaining solutions. Since the operating environment is generally not known a priori to deployment of a robotic sensor network, an adaptive model-free extremum seeking (ES) algorithm is presented to control the motion of 2D nonholonomic vehicles acting as communication relays. Even without specific knowledge of the SNR field, the ES algorithm is able to drive the team of vehicles to optimal locations with only local measures of the SNR. A specific application using unmanned aircraft is simulated to highlight the fact that the performance of the ES chaining algorithm is limited due to the performance constraints and capabilities of the individual vehicles within the chain.