Distributed Coordination of Microwave Wireless Systems at the Wavelength Level

Research on cooperative technologies for distributed wireless systems has focused on increasingly precise coordination between networked nodes. Coordination at the level of the RF wavelength supports coherent operations, such as beamforming from distributed antenna arrays, which has the potential to lead to significant advances in communication and sensing in future systems. Wavelength-level distributed array coordination requires accurate estimation and control of the electrical states of individual elements in the network, including wireless time synchronization, frequency alignment, and phase coherence through high-accuracy relative range estimation. In this talk I will discuss the challenges involved in distributed phase-coherent coordination of wireless systems and recent research on technologies that address these challenges. I will present approaches to high-accuracy range estimation, which yields sub-millimeter range measurements between systems using spectrally-sparse waveforms. Wireless frequency synchronization technologies will be presented, including centralized and decentralized approaches. I will also discuss approaches to wireless time synchronization that are able to achieve picosecond timing accuracy. Experimental implementations of distributed beamforming systems based on these technologies will be shown. Finally, I will present research on new applications in sensing and communications based on the use of distributed and dynamic antenna array systems.