Time synchronization and reach-back communications with pulse-coupled oscillators for UWB wireless ad hoc networks

Time synchronization has been an extremely difficult issue for wireless ad hoc networks due to its decentralized nature. Interestingly, synchrony have often been observed in swarms of biological systems such as that of synchronous flashing fireflies or spiking of neurons. In this paper, we utilize the narrow pulse characteristics of UWB systems to emulate the pulse-coupled integrate-and-fire (IF) model embedded in biological swarms in order to achieve distributed synchronization. The method is based on a simple transmission strategy where nodes integrate the coupling caused by the signal pulses received from other nodes, and fire a pulse after reaching a designated threshold. With time synchronization, many cooperative strategies can be applied to the network of distributed nodes. In particular, we show that synchronization can lead to coherent superposition of the signal pulses and it would allow to utilize the network as a distributed antenna array capable of reaching far receivers, solving the so called reach-back problem.