Collaborative Synchronization for Signal Reinforcement in Sensor Networks

Nodes in sensor fields and in autonomous swarms of mobile robots need to communicate; this usually requires individual nodes to either consume a significant amount of energy, carefully position themselves, precisely align carrier phase, or use complex coding. We propose an alternative strategy of allowing multiple independent and mobile wireless transmitters to share the power-consumption burden by combining low-power transmissions into a unified higher-power transmission. This is not a distributed beamforming or space-time coding approach. Instead, all nodes simultaneously broadcast the same symbol on the same channel without using different code books and without aligning carriers. This paper describes modulation, synchronization, and node selection schemes which make this possible. It also covers both baseband and over-the-air test results.